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Engine Control System - 4.3l (Introduction) Chevrolet Chevy Express G3500

Testing & Diagnostics 51 illustrations ~23086 words

Temperature vs Resistance

°C°FOHMS
Temperature vs Resistance Values (Approximate)
15030247
14028460
13026677
120248100
110230132
100212177
90194241
80176332
70158467
60140667
50122973
451131188
401041459
35951802
30862238
25772796
20683520
15594450
10505670
5417280
0329420
52312300
101416180
15521450
20428680
302252700
4040100700

Temperature vs Resistance

Altitude vs Barometric Pressure

Altitude Measured in Meters (m)Altitude Measured in Feet (ft)Barometric Pressure Measured in Kilopascals (kPa)
Determine your altitude by contacting a local weather station or by using another reference source.
4 26714,00056-64
3 96213,00058-66
3 65812,00061-69
3 35311,00064-72
3 04810,00066-74
2 7439,00069-77
2 4388,00071-79
2 1347,00074-82
1 8296,00077-85
1 5245,00080-88
1 2194,00083-91
9143,00087-95
6102,00090-98
3051,00094-102
00 Sea Level96-104
3051,000101-105

Altitude vs Barometric Pressure

Ignition System Specifications

ApplicationSpecification
MetricEnglish
Firing Order1-6-5-4-3-2
Spark Plug Wire Resistance1,000 ohms per ft
Spark Plug Torque15 N.m11 lb ft
Spark Plug Gap1.52 mm0.06 in
Spark Plug TypeR41-932 [AC plug type]

Ignition System Specifications

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Accelerator Control Cable Bracket Fasteners12 N.m106 lb in
Accelerator Pedal Assembly Mounting Bolts5 N.m44 lb in
AIR Hose Assembly Mounting Bolts25 N.m18 lb ft
AIR Hose Assembly Retainer Bolts40 N.m30 lb ft
AIR Hose Retainer Clip Locknut10 N.m89 lb in
AIR Pump Assembly Hold-Down Block Bolt25 N.m18 lb ft
AIR Pump Assembly Mounting Bolts25 N.m18 lb ft
AIR Solenoid Mounting Bracket Fastener4 N.m35 lb in
Air Cleaner Assembly Bolts18 N.m13 lb ft
Air Cleaner Outlet Duct Nut2 N.m18 lb in
Air Cleaner Outlet Resonator Adapter Stud8 N.m71 lb in
Air Shield Mounting Bolts33 N.m24 lb ft
Camshaft Position Sensor Screws2.2 N.m20 lb in
Crankshaft Position Sensor Mounting Bolt8 N.m71 lb in
Distributor Cap Screws2.4 N.m21 lb in
Distributor Mounting Clamp Bolt25 N.m18 lb ft
Distributor Rotor Retaining Screws2 N.m18 lb in
Distributor Rotor to Reluctor Wheel Screws19.5 N.m14 lb ft
EGR Pipe to Exhaust Manifold25 N.m18 lb ft
EGR Pipe to Intake Manifold10 N.m89 lb in
EGR Retaining Fastener to Pipe Bracket25 N.m18 lb ft
EGR Valve Attaching Bolts25 N.m18 lb ft
Engine Coolant Temperature (ECT) Sensor20 N.m15 lb ft
Evaporative Emission (EVAP) Canister Bracket Bolt12 N.m106 lb in
Exhaust Gas Recirculation (EGR) Pipe to Exhaust Manifold Fittings30 N.m22 lb ft
Fuel and EVAP Pipe Retainer Nut28 N.m21 lb ft
Fuel Fill Hose Clamp2.75 N.m24 lb in
Fuel Injector Retainer Locknuts3 N.m27 lb in
Fuel Pipe Attaching Nuts27 N.m20 lb ft
Fuel Pipe Bracket Retaining Bolt6 N.m53 lb in
Fuel Pipe Fittings27 N.m20 lb ft
Fuel Pipe Retainer Clip Nut28 N.m21 lb ft
Fuel Pipe Retainer Nuts3 N.m27 lb in
Fuel Pipe Retaining Clips Bolts12 N.m106 lb in
Fuel Tank Strap Attaching Bolts20.5 N.m15 lb ft
Heated Oxygen Sensor (HO2S)42 N.m31 lb ft
Idle Air Control (IAC) Valve Attaching Fastener3 N.m27 lb in
Ignition Coil Mounting Screws11 N.m97 lb in
Ignition Control Module (ICM) Mounting Screws3.5 N.m31 lb in
Knock Sensor (KS) Bolt25 N.m18 lb ft
Mass Air Flow (MAF) Sensor Clamps4 N.m35 lb in
Powertrain Control Module (PCM) Connector End Fasteners8 N.m71 lb in
Purge Valve Mounting Nuts12 N.m106 lb in
Spark Plugs - New Aluminum Heads20 N.m15 lb ft
Spark Plugs - New Iron Heads30 N.m22 lb ft
Spark Plugs - Used Heads15 N.m11 lb ft
Steering Linkage Shield Mounting Bolts33 N.m24 lb ft
Throttle Body Assembly Retaining Studs9 N.m80 lb in
Throttle Position (TP) Sensor Fasteners2 N.m18 lb in
Upper Manifold Bolts8 N.m71 lb in
Upper Manifold Nuts8 N.m71 lb in
Vacuum Module Attaching Bolts8 N.m71 lb in

Fastener Tightening Specifications

Action Taken When the DTC Sets - Type A

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

Action Taken When the DTC Sets - Type B

The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.

Conditions for Clearing the MIL/DTC - Type A or Type B

  1. The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  2. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  3. Use a scan tool in order to clear the MIL and the DTC.

Action Taken When the DTC Sets - Type C

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The MIL will not illuminate.
  3. The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC - Type C

  1. A last test failed, or current DTC, clears when the diagnostic runs and passes.
  2. Use a scan tool in order to clear the DTC.

Conditions for Clearing the DTC - Type X

This DTC is available in the PCM software, but has been disabled, or turned OFF. In this case, the diagnostic does not run, no DTCs are stored, and the MIL does not illuminate. Type X DTCs are used primarily for export vehicles that do not require MIL illumination or DTC storing.

Diagnostic Trouble Code (DTC) Type(s)

DescriptionFederal and California Emissions, Less than 8600 GVW, 4.3L LU3Unleaded Fuel Export 4.3L LU3
DTC P0016BB
DTC P0101BB
DTC P0102BB
DTC P0103BB
DTC P0106BB
DTC P0107BB
DTC P0108BB
DTC P0112BB
DTC P0113BB
DTC P0116BB
DTC P0117BB
DTC P0118BB
DTC P0121BB
DTC P0122BB
DTC P0123BB
DTC P0125BB
DTC P0128BB
DTC P0131BB
DTC P0132BB
DTC P0133BB
DTC P0134BB
DTC P0135BB
DTC P0137BB
DTC P0138BB
DTC P0140BB
DTC P0141BB
DTC P0151BB
DTC P0152BB
DTC P0153BB
DTC P0154BB
DTC P0155BB
DTC P0157BB
DTC P0158BB
DTC P0160BB
DTC P0161BB
DTC P0171BB
DTC P0172BB
DTC P0174BB
DTC P0175BB
DTC P0200BB
DTC P0218CC
DTC P0230BB
DTC P0300BB
DTC P0315AA
DTC P0325BB
DTC P0327BB
DTC P0335BB
DTC P0336BB
DTC P0341BB
DTC P0351BB
DTC P0420AA
DTC P0430AA
DTC P0442AX
DTC P0443BB
DTC P0446AA
DTC P0449BB
DTC P0452BB
DTC P0453BB
DTC P0455AA
DTC P0461CC
DTC P0462CC
DTC P0463CC
DTC P0496BB
DTC P0502BB
DTC P0503BB
DTC P0506BB
DTC P0507BB
DTC P0522CC
DTC P0523CC
DTC P0562CC
DTC P0563CC
DTC P0601AA
DTC P0602AA
DTC P0604AA
DTC P0608CC
DTC P0609CC
DTC P0641BB
DTC P0650BB
DTC P0651BB
DTC P0706CC
DTC P0711CC
DTC P0712CC
DTC P0713CC
DTC P0719CC
DTC P0724CC
DTC P0740BB
DTC P0741BB
DTC P0742BB
DTC P0748CC
DTC P0751BB
DTC P0752BB
DTC P0753BB
DTC P0756AA
DTC P0757AA
DTC P0758AA
DTC P0785BB
DTC P0894BB
DTC P1106CC
DTC P1107CC
DTC P1111CC
DTC P1112CC
DTC P1114CC
DTC P1115CC
DTC P1121CC
DTC P1122CC
DTC P1133BB
DTC P1153BB
DTC P1380CX
DTC P1381CX
DTC P1626CC
DTC P1631CC
DTC P1637CC
DTC P1638CC
DTC P1683BB
DTC P1810BB
DTC P1860BB
U1026CC
U1041CC
U1056CC
U1064CC
U1300CC
U1301CC

Diagnostic Trouble Code (DTC) Type(s)

Scheme 89

Scheme 89: Emission Hose Routing Diagram
Scheme 89: Emission Hose Routing Diagram
CalloutComponent Name
1To EVAP Canister
2To AIR Pump (If Applicable)
3Positive Crankcase Ventilation (PCV)
4To HVAC (If Applicable)
5Throttle Body
6Manifold Absolute Pressure (MAP) Sensor
7Crankcase Vent
8EVAP Canister Purge Solenoid Valve
9AIR Pump (If Applicable)
10EVAP Service Port
11EVAP Canister Purge Hose

Scheme 90

Scheme 90: Evaporative Emissions (EVAP) Hose Routing Diagram
Scheme 90: Evaporative Emissions (EVAP) Hose Routing Diagram
CalloutComponent Name
1EVAP Canister Purge Solenoid Valve
2EVAP Canister
3Fuel Fill Neck/Fill Cap
4Rollover Valve/Fuel Tank Pressure (FTP) Sensor
5Fuel Tank
6EVAP Canister Vent Solenoid Valve
7Vent Hose/Pipe
8EVAP Vapor Pipe
9EVAP Purge Pipe
10EVAP Service Port

Scheme 91

Scheme 91: Fuel Hose/Pipes Routing Diagram
Scheme 91: Fuel Hose/Pipes Routing Diagram
CalloutComponent Name
1Fuel Feed Pipe
2Fuel Return Pipe
3Fuel Filter

Engine Controls Schematic Icons

Engine Controls Schematic Icons Icon Icon Definition NOTE: The OBD II symbol is used on the circuit diagrams in order to alert the technician that the circuit is essential for proper OBD II emission control circuit operation. Any circuit which fails and causes the malfunction indicator lamp (MIL) to turn ON, or causes emissions-related component damage, is identified as an OBD II circuit. IMPORTANT: Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. If the wires were covered with shielding, install new shielding. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)

Scheme 92

Scheme 92: Engine Controls Schematic Icons
Scheme 92: Engine Controls Schematic Icons

Scheme 93

Scheme 93
Scheme 93

Scheme 94

Scheme 94: Engine Controls Schematics
Scheme 94: Engine Controls Schematics

Scheme 95

Scheme 95
Scheme 95

Scheme 96

Scheme 96
Scheme 96

Scheme 97

Scheme 97
Scheme 97

Scheme 98

Scheme 98
Scheme 98

Scheme 99

Scheme 99
Scheme 99

Scheme 100

Scheme 100
Scheme 100

Scheme 101

Scheme 101
Scheme 101

Scheme 102

Scheme 102
Scheme 102

Scheme 103

Scheme 103: Engine Controls Component Views
Scheme 103: Engine Controls Component Views
CalloutComponent Name
1Generator
2A/C Compressor Clutch Connector (C60)
3Crankshaft Position (CKP) Sensor Connector

Scheme 104

Scheme 104
Scheme 104
CalloutComponent Name
1Central Sequential Fuel Injection (Central SFI) Connector
2Manifold Air Pressure (MAP) Sensor Connector
3Ignition Control Module (ICM) Connector
4Generator Connector
5S102
6Ignition Coil Connector
7Evaporative Emission (EVAP) Canister Purse Solenoid Connector

Scheme 105

Scheme 105
Scheme 105
CalloutComponent Name
1S101
2A/C Compressor Clutch Connector (C60)
3Throttle Position (TP) Sensor Connector
4Idle Air Control (IAC) Valve Connector
5A/C High Pressure Switch Connector (C60)

Scheme 106

Scheme 106
Scheme 106
CalloutComponent Name
1A/C High Pressure Switch Connector (C60)
2Engine Coolant Temperature (ECT) Sensor Connector

Scheme 107

Scheme 107
Scheme 107
CalloutComponent Name
1G102
2Camshaft Position (CMP) Sensor Connector
3G103
4Engine Oil Pressure (EOP) Sensor Connector
5Knock Sensor (KS) Connector
6Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 Connector

Scheme 108

Scheme 108
Scheme 108
CalloutComponent Name
1S101
2C109
3Powertrain Control Module (PCM) C1, C2
4Fuse Block Underhood - C6
5Fuse Block Underhood - C1
6Horn Assembly Connector
7C100
8C101
9A/C Compressor Clutch Connector (C60)

Scheme 109

Scheme 109
Scheme 109
CalloutComponent Name
1Blower Motor Resistor Assembly
2Blower Motor
3Intake Air Temperature (IAT)/Mass Air Flow (MAF) Sensor
4A/C Low Pressure Switch (C60)

Scheme 110

Scheme 110
Scheme 110
CalloutComponent Name
1Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1
2Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1
3Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2
4Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2
5Park/Neutral Position (PNP) Switch

Scheme 111

Scheme 111
Scheme 111
CalloutComponent Name
1Evaporative Emission (EVAP) Canister Vent Solenoid
2Electronic Brake Control Module (EBCM)

Scheme 112

Scheme 112
Scheme 112
CalloutComponent Name
1Fuel Pump and Sender Assembly Connector
2Fuel Tank Pressure (FTP) Sensor Connector

Powertrain Control Module (PCM) Connector End Views

Powertrain Control Module (PCM) - C1 Connector End Connector Part Information 12191489 80-Way F Micro-Pack 100W Sealed (BU) Pin Wire Color Circuit No. Function 1 BK/WH 1551 Ground 2 L-GN 1867 12-Volt Reference 3 - - Not Used 4 L-BU/BK 844 Fuel Injector 4 Control 5-6 - - Not Used 7 GY 2705 5-Volt Reference A 8 GY 2701 5-Volt Reference A 9 D-BU 496 Knock Sensor 1 Signal 10-11 - - Not Used 12 YE 573 CKP Sensor Signal 13-16 - - Not Used 17 D-BU 1225 Transmission Fluid Pressure Switch Signal B 18 OG 1226 Transmission Fluid Pressure Switch Signal C (Late Production) RD 1226 Transmission Fluid Pressure Switch Signal C (Early Production) 19 PK 439 Ignition 1 Voltage 20 RD/WH 440 Battery Positive Voltage (Late Production) OG 440 Battery Positive Voltage (Early Production) 21 PU 574 Low Reference 22 - - Not Used 23 TN 2759 Low Reference (Late Production) BK 2759 Low Reference (Early Production) 24 BK/WH 1551 Ground 25 TN 1671 HO2S Low Signal - Bank 2 Sensor 2 26 TN 1667 HO2S Low Signal - Bank 2 Sensor 1 27 BK/WH 1551 Ground 28 TN/WH 1669 HO2S Low Signal - Bank 1 Sensor 2 29 TN/WH 1653 HO2S Low Signal - Bank 1 Sensor 1 30-31 - - Not Used 32 TN/WH 771 Transmission Range Switch Signal A (Late Production) BK/WH 771 Transmission Range Switch Signal A (Early Production) 33 PU 420 TCC Brake Switch/Cruise Control Release Signal 34 WH 776 Transmission Range Switch Signal P 35 - - Not Used 36 TN 1744 Fuel Injector 1 Control (Late Production) BK 1744 Fuel Injector 1 Control (Early Production) 37 PK/BK 1746 Fuel Injector 3 Control 38 - - Not Used 39 YE/BK 625 Starter Enable Relay Control 40 BK/WH 1551 Ground 41-42 - - Not Used 43 TN/WH 845 Fuel Injector 5 Control (Late Production) BK/WH 845 Fuel Injector 5 Control (Early Production) 44-45 - - Not Used 46 GY 2709 5-Volt Reference B 47 - - Not Used 48 GY 597 5-Volt Reference A 49 GY 1716 Low Reference 50-52 - - Not Used 53 TN 2762 Low Reference (Late Production) BK 2762 Low Reference (Early Production) 54 OG/BK 469 Low Reference 55-56 - - Not Used 57 RD/WH 440 Battery Positive Voltage (Late Production) OG 440 Battery Positive Voltage (Early Production) 58 D-GN 1049 Class 2 Serial Data 59 YE 710 Class 2 Serial Data (Early Production) 60 TN 2752 Low Reference (Late Production) BK 2752 Low Reference (Early Production) 61 PK/BK 632 Low Reference 62 - - Not Used 63 BK 2755 Low Reference 64 BK/WH 1551 Ground 65 PU 1670 HO2S High Signal - Bank 2 Sensor 2 66 PU 1666 HO2S High Signal - Bank 2 Sensor 1 67 BK/WH 1551 Ground 68 PU/WH 1668 HO2S High Signal - Bank 1 Sensor 2 69 PU/WH 1665 HO2S High Signal - Bank 1 Sensor 1 70 BN 1174 Oil Level Switch Signal 71 - - Not Used 72 YE 772 Transmission Range Switch Signal B 73 BN/WH 633 CMP Sensor Signal 74 YE 410 ECT Sensor Signal 75 PK 1020 Ignition 0 Voltage 76 L-GN/BK 1745 Fuel Injector 2 Control 77 YE/BK 846 Fuel Injector 6 Control 78 - - Not Used 79 WH 687 3-2 Shift Solenoid Valve Control 80 TN 2761 Low Reference (Late Production) BK 2761 Low Reference (Early Production)

Powertrain Control Module (PCM) - C2 Connector End Connector Part Information 12191488 80-Way F Micro-Pack 100W Sealed (GN) Pin Wire Color Circuit No. Function 1 BK/WH 1551 Ground 2 BN 418 TCC PWM Solenoid Valve Control 3-5 - - Not Used 6 OG/BK 1228 PC Solenoid Valve High Control (Late Production) RD/BK 1228 PC Solenoid Valve High Control (Early Production) 7 - - Not Used 8 L-BU/WH 1229 PC Solenoid Valve Low Control 9 D-GN/WH 465 Fuel Pump Relay Control - Primary 10-12 - - Not Used 13 L-BU/BK 396 Cruise Control Engaged Signal 14 - - Not Used 15 OG 225 Generator Turn On Signal (Late Production) RD 225 Generator Turn On Signal (Early Production) 16 - - Not Used 17 D-GN/WH 2523 A/C Request Signal (C60) 18-19 - - Not Used 20 PU 401 Signal Low - Front 21 YE 400 Signal High - Front 22-23 - - Not Used 24 D-BU 411 TP Sensor Signal 25 TN 472 IAT Sensor Signal 26 WH 423 IC Timing Control 27-30 - - Not Used 31 YE 492 MAF Sensor Signal 32 L-GN 432 MAP Sensor Signal 33 - - Not Used 34 D-GN/WH 428 EVAP Canister Purge Solenoid Control 35-36 - - Not Used 37 D-GN 83 Cruise Control Inhibit Signal 38 - - Not Used 39 OG 631 12-Volt Reference (Late Production) RD 631 12-Volt Reference (Early Production) 40 BK/WH 1551 Ground 41 - - Not Used 42 TN/BK 422 TCC Solenoid Valve Control 43 D-GN/WH 459 A/C Compressor Clutch Relay Control (C60) 44 - - Not Used 45 WH 1310 EVAP Canister Vent Solenoid Control 46 BN/WH 419 MIL Control 47 YE/BK 1223 2-3 Shift Solenoid Valve Control 48 L-GN 1222 1-2 Shift Solenoid Valve Control 49 YE/BK 1827 Vehicle Speed Signal 50 D-GN/WH 817 Vehicle Speed Signal 51 YE/BK 1227 TFT Sensor Signal 52 PU 5035 HO2S Heater Low Control - Bank 1 Sensor 2 53 YE 5036 HO2S Heater Low Control - Bank 2 Sensor 2 54 PU 1589 Fuel Level Sensor Signal 55 D-GN 603 A/C Low Pressure Switch Signal (C60) 56 - - Not Used 57 TN 470 Low Reference (Late Production) BK 470 Low Reference (Early Production) 58 TN/WH 331 Oil Pressure Sensor Signal 59 PU 806 Crank Voltage 60-61 - - Not Used 62 GY 773 Transmission Range Switch Signal C 63 PK 1224 Transmission Fluid Pressure Switch Signal A 64 D-GN 890 Fuel Tank Pressure Sensor Signal 65-71 - - Not Used 72 L-BU 5038 HO2S Heater Low Control - Bank 1 Sensor 1 73 - - Not Used 74 PU/WH 5037 HO2S Heater Low Control - Bank 2 Sensor 1 75 GY 23 Generator Field Duty Cycle Signal 76 L-GN/WH 1749 IAC Coil B High Control 77 L-GN/BK 444 IAC Coil B Low Control 78 L-BU/BK 1748 IAC Coil A Low Control 79 L-BU/WH 1747 IAC Coil A High Control 80 - - Not Used

Engine Controls Connector End Views

Camshaft Position (CMP) Sensor Connector End Connector Part Information 12110293 3-Way F Metri-Pack 150 Series- Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 632 Low Reference B BN/WH 633 CMP Sensor Signal C OG 631 12-Volt Reference (Late Production) RD 631 12-Volt Reference (Early Production)

Central Sequential Fuel Injection Connector End (Central SFI) Connector Part Information 12177083 12-Way F Micro-Pack 100 Series (BK) Pin Wire Color Circuit No. Function A TN/WH 845 Fuel Injector 5 Control (Late Production) BK/WH 845 Fuel Injector 5 Control (Early Production) B PK 139 Ignition 1 Voltage C PK/BK 1746 Fuel Injector 3 Control D PK 139 Ignition 1 Voltage E PK 139 Ignition 1 Voltage F TN 1744 Fuel Injector 1 Control (Late Production) BK 1744 Fuel Injector 1 Control (Early Production) G L-GN/BK 1745 Fuel Injector 2 Control H PK 239 Ignition 1 Voltage J PK 239 Ignition 1 Voltage K L-BU/BK 844 Fuel Injector 4 Control L PK 239 Ignition 1 Voltage M YE/BK 846 Fuel Injector 6 Control

Crankshaft Position (CKP) Sensor Connector End Connector Part Information 15324165 3-Way F Metri-Pack 150 Series (NA) Pin Wire Color Circuit No. Function A L-GN 1867 12-Volt Reference B PU 574 Low Reference C YE 573 CKP Sensor Signal

Engine Coolant Temperature (ECT) Sensor Connector End Connector Part Information 15359366 2-Way F GT 150 Sealed (BK) Pin Wire Color Circuit No. Function A TN 2761 Low Reference (Late Production) BK 2761 Low Reference (Early Production) B YE 410 ECT Sensor Signal

Evaporative Emission (EVAP) Canister Purge Solenoid Valve Connector End Connector Part Information 12124037 2-Way F Metri-Pack 150 Series- Sealed (BK) Pin Wire Color Circuit No. Function A PK 139 Ignition 1 Voltage B D-GN/WH 428 EVAP Canister Purge Solenoid Control

Evaporative Emission (EVAP) Canister Vent Solenoid Valve Connector End Connector Part Information 12052643 2-Way F Metri-Pack 150 Series- Sealed (RD) Pin Wire Color Circuit No. Function A RD/WH 140 Battery Positive Voltage (Late Production) OG 140 Battery Positive Voltage (Early Production) B WH 1310 EVAP Canister Vent Solenoid Control

Fuel Pump & Sender Assembly Connector End Connector Part Information 15326631 4-Way F GT 280 Sealed 5.8 (BK) Pin Wire Color Circuit No. Function A BK 150 Ground B PU 1589 Fuel Level Sensor Signal C TN 2759 Low Reference (Late Production) BK 2759 Low Reference (Early Production) D GY 120 Fuel Pump Supply Voltage

Fuel Tank Pressure (FTP) Sensor Connector End Connector Part Information 12059595 3-Way F Metri-Pack 150 Series- Sealed (BK) Pin Wire Color Circuit No. Function A TN 2759 Low Reference (Late Production) BK 2759 Low Reference (Early Production) B D-GN 890 Fuel Tank Pressure Sensor Signal C GY 2709 5-Volt Reference B

Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 Connector End Connector Part Information 15326423 4-Way M Metri-Pack 150 Sealed (GY) Pin Wire Color Circuit No. Function A TN/WH 1653 HO2S Low Signal - Bank 1 Sensor 1 B PU/WH 1665 HO2S High Signal - Bank 1 Sensor 1 C L-BU 5038 HO2S Heater Low Control - Bank 1 Sensor 1 D PK 539 Ignition 1 Voltage

Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2 Connector End Connector Part Information 15326423 4-Way M Metri-Pack 150 Sealed (GY) Pin Wire Color Circuit No. Function A TN/WH 1669 HO2S Low Signal - Bank 1 Sensor 2 B PU/WH 1668 HO2S High Signal - Bank 1 Sensor 2 C PU 5035 HO2S Heater Low Control - Bank 1 Sensor 2 D PK 1539 Ignition 1 Voltage

Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1 Connector End Connector Part Information 12160825 4-Way M Metri-Pack 150 Sealed (BK) Pin Wire Color Circuit No. Function A TN 1667 HO2S Low Signal - Bank 2 Sensor 1 B PU 1666 HO2S High Signal - Bank 2 Sensor 1 C PU/WH 5037 HO2S Heater Low Control - Bank 2 Sensor 1 D PK 539 Ignition 1 Voltage

Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2 Connector End Connector Part Information 12160825 4-Way M Metri-Pack 150 Sealed (BK) Pin Wire Color Circuit No. Function A TN 1671 HO2S Low Signal - Bank 2 Sensor 2 B PU 1670 HO2S High Signal - Bank 2 Sensor 2 C YE 5036 HO2S Heater Low Control - Bank 2 Sensor 2 D PK 1539 Ignition 1 Voltage

Idle Air Control (IAC) Valve Connector End Connector Part Information 15354716 4-Way F GT 150 Sealed 3.2 X 4.0 (BK) Pin Wire Color Circuit No. Function A L-GN/BK 444 IAC Coil B Low Control B L-GN/WH 1749 IAC Coil B High Control C L-BU/BK 1748 IAC Coil A Low Control D L-BU/WH 1747 IAC Coil A High Control

Ignition Coil Connector End Connector Part Information 12146121 3-Way F Metri-Pack 150 Series- Sealed (BN) Pin Wire Color Circuit No. Function A PK 239 Ignition 1 Voltage B - - Not Used C WH/BK 1847 Ignition Coil Control

Ignition Control Module (ICM) Connector End Connector Part Information 15355331 4-Way F GT 150 SLD 3.2 x 4.0 (BK) Pin Wire Color Circuit No. Function A PK 139 Ignition 1 Voltage B WH 423 IC Timing Control C BK 1250 Ground D WH/BK 1847 Ignition Coil Control

Intake Air Temperature (IAT)/Mass Air Flow (MAF) Sensor Connector End Connector Part Information 15326822 5-Way F GT 150 Sealed 4.0 (BK) Pin Wire Color Circuit No. Function A YE 492 MAF Sensor Signal B PK 139 Ignition 1 Voltage C BK/WH 1551 Ground D TN 472 IAT Sensor Signal E TN 470 Low Reference (Late Production) BK 470 Low Reference (Early Production)

Knock Sensor (KS) Connector End Connector Part Information 12129140 2-Way F Metri-Pack 280.1 - Pull To Seat (BK) Pin Wire Color Circuit No. Function A D-BU 496 Knock Sensor 1 Signal B GY 1716 Low Reference

Manifold Absolute Pressure (MAP) Sensor Connector End Connector Part Information 12129946 3-Way F Metri-Pack 150 Series- Sealed (GY) Pin Wire Color Circuit No. Function A OG/BK 469 Low Reference B L-GN 432 MAP Sensor Signal C GY 597 5-Volt Reference A

Throttle Position (TP) Sensor Connector End Connector Part Information 15344137 3-Way F GT 150 Sealed 5.2 (BK) Pin Wire Color Circuit No. Function 1 GY 2701 5-Volt Reference A 2 TN 2752 Low Reference (Late Production) BK 2752 Low Reference (Early Production) 3 D-BU 411 TP Sensor Signal

Powertrain Control Module (PCM) Replacement

Note. Turn the ignition OFF when installing or removing the PCM connectors and disconnecting or reconnecting the power to the PCM (battery cable, PCM pigtail, PCM fuse, jumper cables, etc.) in order to prevent internal PCM damage.

Service of the powertrain control module (PCM) should normally consist of either replacement of the PCM or electrically erasable programmable read only memory (EEPROM) programming. If the diagnostic procedures call for the PCM to be replaced, the PCM should be inspected first to see if the correct part is being used. If the correct part is being used, remove the faulty PCM and install the new service PCM.

IMPORTANTRemove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM module connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the PCM.
IMPORTANTThe replacement PCM must be programmed.

Removal Procedure

  1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
  2. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
  3. Disconnect the PCM harness connectors.
  4. Release the spring latch from the PCM.
  5. Lift the PCM from the PCM mounting tray.
  6. Remove the PCM from the engine compartment.

Installation Procedure

  1. Install the PCM to the PCM mounting tray.
  2. Secure the spring latch to the PCM.
  3. Connect the PCM connectors to the PCM. Tighten: Tighten the PCM connector end fasteners to 8 N.m (71 lb in).
  4. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
  5. If a new PCM is being installed, program the PCM. Refer to «Service Programming System (SPS)»(/chevrolet/chevy-express-g3500/1996-2012/remont/communication-devices/#service-programming-system) in Programming.

CKP System Variation Learn Procedure

  1. Install a scan tool.
  2. Monitor the powertrain control module (PCM) for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to «Diagnostic Trouble Code (DTC) List»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-diagnostic-information-procedures__diagnostic-trouble-code-dtc-list) for the applicable DTC that set.
  3. Select the crankshaft position variation learn procedure with a scan tool.
  4. The scan tool instructs you to perform the following: Accelerate to wide open throttle (WOT). Release throttle when fuel cut-off occurs. Engine should not accelerate beyond calibrated RPM value. Release throttle immediately if value is exceeded. Block drive wheels. Set parking brake. DO NOT apply brake pedal. Cycle ignition from OFF to ON. Apply and hold brake pedal. Start and idle engine. Turn A/C OFF. Vehicle must remain in Park or Neutral. The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components: Crankshaft position (CKP) sensors activity - If there is a CKP sensor condition, refer to the applicable DTC that set. Camshaft position (CMP) sensor activity - If there is a CMP sensor condition, refer to the applicable DTC that set. Engine coolant temperature (ECT) - If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
  5. Enable the crankshaft position system variation learn procedure with the scan tool.
  6. Accelerate to WOT.
  7. Release when the fuel cut-off occurs.
  8. The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to «DTC P0315»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-diagnosis-43l-dtc-p0140-to-p2610) . If any other DTCs set, refer to «Diagnostic Trouble Code (DTC) List»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-diagnostic-information-procedures__diagnostic-trouble-code-dtc-list) for the applicable DTC that set.
  9. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.
  10. The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set. An engine replacement A PCM replacement A harmonic balancer replacement A CKP sensor replacement Any engine repairs which disturb the CKP sensor relationship

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. Turn OFF the ignition.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Drain the coolant below the level of the ECT sensor. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
  4. Disconnect the electrical connector.
  5. Carefully remove the ECT sensor.

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. Coat the threads with sealer GM P/N 9985253 or equivalent.
  2. Install the ECT sensor. Tighten: Tighten the ECT sensor to 20 N.m (15 lb ft).
  3. Connect the ECT sensor harness connector to the ECT sensor.
  4. Refill the cooling system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
  5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Turn OFF the ignition.
  2. Disconnect the mass air flow (MAF) sensor harness connector.
  3. Loosen the clamps (1) on the MAF sensor.
  4. Carefully remove the MAF sensor from the air intake ducts (5).
  1. Install the MAF sensor (5) into the air intake ducts.
  2. Tighten the clamps (1) on the MAF sensor. Tighten: Tighten the clamps to 4 N.m (35 lb in).
  3. Connect the MAF sensor harness connector.

Other than checking for a worn grommet and loose electrical connectors, the only service possible is a unit replacement if the diagnosis shows a malfunctioning manifold absolute pressure (MAP) sensor.

  1. Turn OFF the ignition.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Disconnect the MAP sensor harness connector.
  4. Remove the MAP sensor by pulling straight up with a slight rocking motion.
  5. Remove the MAP sensor grommet.
  6. Discard the MAP sensor grommet.
  1. Install the new MAP sensor grommet on the MAP sensor.
  2. Install the MAP sensor.
  3. Connect the MAP sensor harness connector.
  4. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Tools Required

J 39194-B Oxygen Sensor Wrench

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the connector (1) for the HO2S.
  3. Remove the HO2S (2) using a J 39194-B .
  1. Coat the threads of the oxygen sensor with anti-seize compound GM P/N 5613695, if necessary.
  2. Install the HO2S (2) using a J 39194-B . Tighten: Tighten the sensor to 42 N.m (31 lb ft).
  3. Connect the HO2S harness connector (1).
  4. Lower the vehicle.

J 39194-B Oxygen Sensor Wrench

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the connector (1) from the HO2S.
  3. Remove the HO2S (2) using a J 39194-B .
  1. Coat the threads of the oxygen sensor with anti-seize compound GM P/N 5613695, if necessary.
  2. Install the HO2S (2) using a J 39194-B . Tighten: Tighten the sensor to 42 N.m (31 lb ft).
  3. Connect the HO2S harness connector (1).
  4. Lower the vehicle.

J 39194-B Oxygen Sensor Wrench

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the connector (1) for the HO2S.
  3. Remove the HO2S (2) using a J 39194-B .
  1. Coat the threads of the oxygen sensor with anti-seize compound GM P/N 5613695, if necessary.
  2. Install the HO2S (2) using a J 39194-B . Tighten: Tighten the sensor to 42 N.m (31 lb ft).
  3. Connect the HO2S harness connector (1).
  4. Lower the vehicle.

J 39194-B Oxygen Sensor Wrench

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the connector (1) for the HO2S.
  3. Remove the HO2S (2) using a J 39194-B .
  1. Coat the threads of the oxygen sensor with anti-seize compound GM P/N 5613695, if necessary.
  2. Install the HO2S (2) using a J 39194-B . Tighten: Tighten the sensor to 42 N.m (31 lb ft).
  3. Connect the HO2S harness connector (1).
  4. Lower the vehicle.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Remove the throttle position (TP) sensor harness connector.
  3. Remove the TP sensor attaching fasteners.
  4. Remove the TP sensor from the throttle body assembly.
  1. With the throttle valve closed, install the TP sensor on the throttle shaft. Rotate the TP sensor counterclockwise in order to align the mounting holes.
  2. Install the TP sensor attaching fasteners. Tighten: Tighten the fasteners to 2 N.m (18 lb in).
  3. Install the TP sensor harness connector.
  4. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Turn OFF the ignition.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Disconnect the harness connector from the idle air control (IAC) valve.
  4. Remove the IAC valve attaching fasteners.
  5. Remove the IAC valve assembly.
  6. Remove the O-ring.

Cleaning & Inspection Procedure

  1. Clean the IAC valve O-ring sealing surface, the pintle valve seat, and the air passage. Use a carburetor cleaner and a parts cleaning brush in order to remove any carbon deposits. Follow the instructions on the container. Do not use a cleaner that contains methyl ethyl ketone (MEK). MEK is an extremely strong solvent and not necessary for this type of deposit. Shiny spots on the pintle or seat are normal and do not indicate misalignment or a bent pintle shaft. If the air passage has heavy deposits, remove the throttle body for a complete cleaning. Refer to «Throttle Body Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  2. Inspect the IAC valve O-ring for cuts, cracks, or distortion. Replace the O-ring if damaged.
  1. Measure the distance between tip of the IAC valve pintle and the mounting flange. If the distance is more than 28 mm (1.10 in), use finger pressure in order to slowly retract the pintle. The force required to retract the pintle of a new valve will not cause damage to the valve.
  2. Lubricate the IAC valve O-ring with clean engine oil.
  3. Install the IAC valve assembly.
  4. Install the attaching fasteners. Tighten: Tighten the IAC valve fasteners to 3 N.m (27 lb in).
  5. Connect the IAC harness connector.
  6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  7. Reset the IAC valve pintle position.

IAC Valve Reset Procedure

  1. Turn ON the ignition for 20 seconds.
  2. Turn OFF the ignition for 10 seconds.
  3. Start the engine.
  4. Check for the proper idle speed.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Remove the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Remove the accelerator cable from the throttle lever.
  4. Remove the accelerator cable from the engine cable bracket.
  5. Remove the accelerator cable from the accelerator pedal (2).
  6. Remove the accelerator cable from the bulkhead (1).
  1. Install the accelerator cable to the bulkhead (1).
  2. Install the accelerator cable to the accelerator pedal (2).
  3. Install the accelerator cable to the engine cable bracket.
  4. Install the accelerator cable to the throttle lever.
  5. Install the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Lift upward on the accelerator pedal (3) to relieve the tension on the cable (2).
  2. Remove the retainer (1) from the pedal lever (4) hole.
  3. Remove the cable from the slot in the pedal lever.
  4. Remove the accelerator pedal mounting fasteners.
  5. Remove the accelerator pedal assembly.
IMPORTANTThe accelerator cable is not to be kinked or damaged in any way during installation. Ensure that the mounting surface between the accelerator pedal assembly and the dash panel is free of insulation. The carpet and padding in the pedal area must be positioned to lay flat and free of wrinkles and bunches. Wires, hoses, cables, and other flexible components should not be within 13 mm (0.52 in) of the cable or lever, at any point in their travel.
  1. Place the accelerator pedal assembly (4) on the mounting surface.
  2. Install the mounting bolts. Tighten: Tighten the pedal assembly to 5 N.m (44 lb in).
  3. Lift upward on the accelerator pedal (3).
  4. Insert the cable (2) through the pedal lever slot.
  5. Press the retainer (1) into the lever hole until fully seated.
  6. Check the pedal (3) for free movement by pressing down on the pedal.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Remove the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  4. Remove the air cleaner outlet adapter stud.
  5. Remove the cruise control cable. Refer to «Cruise Control Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cruise-control-systems/#cruise-control-system) in Cruise Control.
  6. Remove the accelerator cable. Refer to «Accelerator Controls Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  7. Remove the stud and nuts retaining the accelerator control cable bracket and position the bracket aside.
  8. Disconnect the idle air control (IAC) valve harness connector.
  9. Disconnect the throttle position (TP) sensor harness connector.
  10. Remove the throttle body retaining studs.
  11. Remove the throttle body assembly.
  12. Discard the throttle body seal.
  1. Clean the gasket surface on the intake manifold.
  2. Install the throttle body assembly with a new seal.
  3. Install the throttle body assembly retaining studs. Tighten: Tighten the studs to 9 N.m (80 lb in).
  4. Install the adapter stud for the air cleaner outlet resonator. Tighten: Tighten the fasteners to 8 N.m (71 lb in).
  5. Connect the TP sensor harness connector.
  6. Connect the IAC valve harness connector.
  7. Install the accelerator control cable bracket using the mounting fasteners. Tighten: Tighten the fasteners to 12 N.m (106 lb in).
  8. Install the accelerator cable.
  9. Install the cruise control cable.
  10. Install the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  11. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  12. Connect the negative battery cable.
  13. Use the following procedure in order to inspect the accelerator pedal operation. Depress the pedal to the floor. Release the accelerator pedal.

Fuel Pressure Relief Procedure

Tools Required

J 34730-1A Fuel Pressure Gage. See Special Tools and Equipment .

CAUTIONRemove the fuel tank cap and relieve the fuel system pressure before servicing the fuel system in order to reduce the risk of personal injury. After you relieve the fuel system pressure, a small amount of fuel may be released when servicing the fuel lines, the fuel injection pump, or the connections. In order to reduce the risk of personal injury, cover the fuel system components with a shop towel before disconnection. This will catch any fuel that may leak out. Place the towel in an approved container when the disconnection is complete.
  1. Turn the ignition OFF.
  2. Disconnect the negative battery cable in order to avoid possible fuel discharge if an accidental attempt is made to start the engine.
  3. Loosen the fuel filler cap in order to relieve the fuel tank vapor pressure.
  4. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  5. Connect the J 34730-1A or the equivalent to the fuel pressure connection. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Wrap a shop towel around the fitting while connecting the gage in order to avoid spillage.
  7. Install the bleed hose of the gage into an approved container.
  8. Open the valve on the gage in order to bleed the system pressure. The fuel connections are now safe for servicing.
  9. Drain any fuel remaining in the gage into an approved container.
  10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

J 34730-1A Fuel Pressure Gage. See Special Tools and Equipment .

CAUTIONGasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Install the J 34730-1A fuel pressure gage to the fuel pressure service connection. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Turn ON the ignition.
  4. Place the bleed hose of the fuel pressure gage into an approved gasoline container.
  5. Open the bleed valve on the fuel pressure gage in order to bleed the air from the fuel pressure gage.
  6. Command the fuel pump ON with a scan tool.
  7. Close the bleed valve on the fuel pressure gage.
  8. Inspect for fuel leaks.
  1. Place the fuel pressure gage bleed hose into an approved container and open the bleed valve to bleed OFF fuel system pressure.
  2. Place a shop towel under the J 34730-1A to catch any remaining fuel spillage. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Remove the J 34730-1A from the fuel pressure connection. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  4. Drain any fuel remaining in the fuel pressure gage into an approved container.
  5. Inspect for leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.
  6. Install the cap on the fuel pressure connection.
  7. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

J 37088-A Fuel Line Quick-Connect Separator. See Special Tools & Equipment .

  1. Relieve the fuel system pressure before servicing any fuel system connection. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  2. Remove the retainer from the quick-connect fitting.
  3. Blow dirt out of the fitting using compressed air.
  4. Choose the correct tool from J 37088-A tool set for the size of the fitting. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) . Insert the tool into the female connector, then push inward to release the locking tabs.
  5. Pull the connection apart.
  6. Using a clean shop towel, wipe off the male pipe end.
  7. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.
  1. Apply a few drops of clean engine oil to the male pipe end.
  2. Push both sides of the fitting together to cause the retaining tabs to snap into place.
  3. Once installed, pull on both sides of the fitting to make sure the connection is secure.
  4. Install the retainer to the quick-connect fitting.
  1. Relieve the fuel system pressure before servicing any fuel system connection. Refer to the «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  2. Using compressed air, blow any dirt out of the quick-connect fitting.
  3. Squeeze the plastic retainer release tabs.
  4. Pull the connection apart.
  1. Apply a few drops of clean engine oil to the male fuel pipe end.
  2. Push both sides of the quick-connect fitting together in order to cause the retaining tabs to snap into place.
  3. Once installed, pull on both sides of the quick-connect fitting in order to make sure the connection is secure.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  4. Clean all the fuel filter connections and the surrounding areas before disconnecting the fuel pipes in order to avoid possible contamination of the fuel system.
  5. Disconnect the fuel feed pipe from the fuel filter outlet.
  6. Disconnect the fuel feed pipe from the fuel filter inlet.
  7. Cap the fuel pipes in order to prevent fuel system contamination.
  8. Remove the fuel filter from the bracket.
  9. Inspect the fuel pipe O-rings for cuts, nicks, swelling, or distortion. Replace the O-rings if necessary.
  1. Install the fuel filter into the bracket.
  2. Remove the caps from the fuel pipes.
  3. Connect the fuel feed pipe to the fuel filter inlet.
  4. Connect the fuel feed pipe to the fuel filter outlet.
  5. Lower the vehicle.
  6. Tighten the fuel filler cap.
  7. Connect the negative battery cable.
  8. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Remove the mounting bolts from the EVAP canister bracket.
  3. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  5. Clean all the fuel filter connections and the surrounding areas before disconnecting the fuel pipes in order to avoid contamination of the fuel system.
  6. Disconnect the fuel feed pipe from the fuel filter outlet.
  7. Disconnect the fuel feed pipe from the fuel filter inlet.
  8. Cap the fuel pipes in order to prevent fuel system contamination.
  9. Remove the fuel filter from the bracket.
  10. Inspect the fuel pipe O-rings for cuts, nicks, swelling, or distortion. Replace the O-rings if necessary.
  1. Install the fuel filter into the bracket.
  2. Remove the caps from the fuel pipes.
  3. Connect the fuel feed pipe to the fuel filter inlet.
  4. Connect the fuel feed pipe to the fuel filter outlet.
  5. Install the mounting bolts to the EVAP canister bracket. Tighten: Tighten the bolts to 12 N.m (106 lb in).
  6. Lower the vehicle.
  7. Tighten the fuel filler cap.
  8. Connect the negative battery cable.
  9. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

Fuel Tank Draining Procedure

CAUTIONGasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.
  1. Disconnect the negative battery cable.
  2. Use a hand operated pump device in order to remove the fuel through the fuel filler pipe.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  5. Clean all fuel pipe and hose connections and surrounding areas before disconnecting the fuel pipes in order to avoid contamination of the fuel system.
  6. Loosen the fuel fill hose clamp.
  7. Disconnect the fuel fill hose from the fuel fill pipe.
  8. Disconnect the rear evaporative emission (EVAP) pipe at the EVAP canister.
  9. With the aid of an assistant, support the fuel tank.
  10. Remove the attaching bolts (1) from the fuel tank strap.
  11. Remove the fuel tank straps (2).
  12. Carefully lower the fuel tank.
  13. Disconnect the fuel feed pipe and the fuel return pipe at the fuel sender. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  14. Disconnect the electrical connectors from the fuel sender and the fuel pressure sensor.
  15. Remove the fuel tank.
  16. Place the fuel tank in a suitable work area.
  17. Cap the open fuel and EVAP pipes on the vehicle in order to prevent possible fuel system contamination.
  18. Remove the EVAP pipe from the roll over valves and the retainer clips.
  19. Remove the fuel sender assembly from the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  20. Remove the fuel fill hose from the fuel tank.
  1. Install the fuel tank insulators (6).
  2. Remove the caps from the fuel and EVAP pipes.
  3. Install the fuel fill hose to the fuel tank. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  4. Install the fuel sender assembly to the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Connect the EVAP pipe to the roll-over valves and the retainer clips.
  6. With the aid of an assistant, position and support the fuel tank.
  7. Raise the fuel tank slightly.
  8. Connect the electrical connectors to the fuel sender and the fuel pressure sensor.
  9. Connect the fuel feed pipe and the fuel return pipe to the fuel sender. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  10. Raise the tank fully.
  11. Install the fuel tank straps (2).
  12. Install the new attaching bolts (1) to the fuel tank strap. Tighten: Tighten the fuel tank strap attaching bolts to 20.5 N.m (15 lb ft).
  13. Connect the rear EVAP pipe (1) to the EVAP canister.
  14. Connect the fuel fill hose to the fuel fill pipe. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  15. Lower the vehicle.
  16. Refill the fuel tank.
  17. Tighten the fuel filler cap.
  18. Connect the negative battery cable.
  19. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  5. Loosen the fuel fill hose clamp.
  6. Disconnect the fuel fill hose from the fuel tank.
  7. Clean all the fuel pipe connections and the surrounding areas before disconnecting the fuel pipes in order to avoid possible contamination of the fuel system.
  8. Disconnect the rear fuel return pipe at the chassis fuel return pipe. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  9. Disconnect the chassis fuel feed pipe at the fuel filter. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  10. Disconnect the chassis evaporative emission (EVAP) purge pipe at the EVAP canister.
  11. Cap the fuel and EVAP pipes in order to prevent fuel system contamination.
  12. With the aid of an assistant, support the fuel tank.
  13. Remove the attaching bolts (4) from the fuel tank strap.
  14. Remove the fuel tank straps (3).
  15. Carefully lower the fuel tank.
  16. Disconnect the fuel sender and the fuel pressure sensor electrical connectors.
  17. Remove the fuel tank.
  18. Place the fuel tank in a suitable work area.
  19. Disconnect the EVAP pipe at the front roll-over valve (5), the rear roll-over valve (2), the EVAP canister (4), and the retainer clips.
  20. Remove the fuel sender assembly and the fuel pipes (6) from the fuel tank and the fuel filter. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  21. Remove the fuel fill hose from the fuel tank.
  22. Remove the fuel tank from the fuel tank shield.
  1. Install the fuel tank insulators (3).
  2. Install the fuel tank into the fuel tank shield.
  3. Install the fuel fill hose to the fuel tank. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  4. Install the fuel sender assembly and the fuel pipes (6) to the fuel tank and the fuel filter. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Connect the EVAP pipe at the front roll-over valve (5), the rear roll-over valve (2), the EVAP canister (4), and the retainer clips.
  6. With the aid of an assistant, position and support the fuel tank.
  7. Raise the fuel tank slightly.
  8. Connect the electrical connectors to the fuel sender and the fuel pressure sensor.
  9. Raise the tank fully.
  10. Install the fuel tank straps (3).
  11. Install the new attaching bolts (4) to the fuel tank strap. Tighten: Tighten the bolts to 20.5 N.m (15 lb ft).
  12. Remove the caps from the fuel and EVAP pipes.
  13. Connect the chassis EVAP purge pipe to the EVAP canister.
  14. Connect the chassis fuel feed pipe to the fuel filter. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  15. Connect the rear fuel return pipe to the chassis fuel return pipe. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  16. Connect the fuel fill hose to the fuel fill pipe. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  17. Lower the vehicle.
  18. Refill the fuel tank.
  19. Tighten the fuel filler cap.
  20. Connect the negative battery cable.
  21. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Raise the vehicle. This must be done with a frame hoist in order to allow the rear suspension to hang. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  5. Loosen the fuel fill hose clamp (2).
  6. Disconnect the fuel fill hose from the fuel tank (1).
  7. Clean all the fuel pipe connections and the surrounding areas before disconnecting the fuel pipes in order to avoid contamination of the fuel system.
  8. Disconnect the rear fuel and evaporative emissions (EVAP) pipes (2) at the chassis fuel and EVAP pipes. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  9. Cap the fuel and EVAP pipes in order to prevent fuel system contamination.
  10. With the aid of an assistant, support the fuel tank.
  11. Remove the attaching bolts (4) from the fuel tank strap.
  12. Remove the fuel tank straps (3).
  13. Carefully lower the fuel tank.
  14. Disconnect the electrical connectors from the fuel sender and the fuel pressure sensor.
  15. Remove the fuel tank.
  16. Place the fuel tank in a suitable work area.
  17. Remove the fuel sender assembly and the rear fuel and EVAP pipes from the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  1. Install the fuel tank insulators.
  2. Install the fuel sender assembly and the rear fuel and EVAP pipes to the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. With the aid of an assistant, position and support the fuel tank.
  4. Raise the fuel tank slightly.
  5. Connect the electrical connectors to the fuel sender and the fuel pressure sensor.
  6. Raise the tank fully.
  7. Install the fuel tank straps (3).
  8. Install the new attaching bolts (4) to the fuel tank strap. Tighten: Tighten the bolts to 20.5 N.m (15 lb ft).
  9. Remove the caps from the fuel and EVAP pipes.
  10. Connect the rear fuel and EVAP pipes (2) to the chassis fuel and EVAP pipes. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  11. Connect the fuel fill hose to the fuel tank (1). Tighten: Tighten the fuel fill hose clamp (2) to 2.75 N.m (24 lb in).
  12. Lower the vehicle.
  13. Refill the fuel tank.
  14. Tighten the fuel filler cap.
  15. Connect the negative battery cable.
  16. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Raise the vehicle.
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel pressure sensor (1).
  1. Install the fuel pressure sensor (1).
  2. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Refill the fuel tank.
  4. Install the fuel filler cap.
  5. Connect the negative battery cable.
  6. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Disconnect the fuel pump electrical connector (5).
  7. Remove the electrical connector retaining clip (6) from the fuel level sensor.
  8. Disconnect the electrical connector (7) from the fuel level sensor under the fuel sender cover.
  9. Remove the retaining clip (4) from the fuel level sensor.
  10. Squeeze the locking tangs and remove the fuel level sensor (3).
  1. Install the fuel level sensor (3).
  2. Install the retaining clip (4) to the fuel level sensor.
  3. Connect the electrical connector (7) to the fuel level sensor.
  4. Connect the electrical connector retaining clip (6) to the fuel level sensor.
  5. Connect the fuel pump electrical connector (5).
  6. Install the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  7. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  8. Refill the fuel tank.
  9. Install the fuel filler cap.
  10. Connect the negative battery cable.
  11. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

Fuel Strainer Replacement

Tools Required

  1. J 34730-1A Fuel Pressure Gage. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  2. J 39765 Fuel Sender Lock Nut Wrench. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Note the position of the fuel strainer (2) on the fuel sender.
  7. Support the fuel sender assembly with one hand and grasp the strainer with the other hand.
  8. Pull the strainer off the fuel sender. Discard the strainer after inspection.
  9. Inspect the strainer. Replace a contaminated strainer and clean the fuel tank.
  1. Install a new fuel strainer (2) in the same position as noted during disassembly. Push the strainer on the bottom of the fuel sender until the strainer is fully seated.
  2. Install the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  4. Refill the fuel tank.
  5. Install the fuel filler cap.
  6. Connect the negative battery cable.
  7. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Note the position of the fuel strainer (2) on the fuel sender.
  7. Support the fuel sender assembly with one hand and grasp the strainer with the other hand.
  8. Pull the strainer off the fuel sender. Discard the strainer after inspection.
  9. Inspect the strainer. Replace a contaminated strainer and clean the fuel tank.
  10. Disconnect the fuel pump electrical connector (5).
  11. Remove the electrical connector retaining clip (6) from the fuel level sensor.
  12. Disconnect the electrical connector (7) from the fuel level sensor under the fuel sender cover.
  13. Remove the retaining clip (4) from the fuel level sensor.
  14. Squeeze the locking tangs and remove the fuel level sensor (3).
  15. Remove the fuel pressure sensor (1).
  1. Install the fuel pressure sensor (1).
  2. Install the fuel level sensor (3).
  3. Install the retaining clip (4) to the fuel level sensor.
  4. Connect the electrical connector (7) to the fuel level sensor.
  5. Connect the electrical connector retaining clip (6).
  6. Connect the fuel pump electrical connector (5). IMPORTANT: Always install a new fuel strainer when replacing the fuel tank fuel pump module.
  7. Install a new fuel strainer (2) in the same position as noted during disassembly. Push the strainer on the bottom of the fuel sender until the strainer is fully seated.
  8. Install the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  9. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  10. Refill the fuel tank.
  11. Tighten the fuel filler cap.
  12. Connect the negative battery cable.
  13. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Clean all the fuel pipe and hose connections and the surrounding areas before disconnecting in order to avoid contamination of the fuel system.
  2. Remove the fuel filler cap.
  3. Drain the fuel below the level of the fuel tank fill hose. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the 2 retaining bolts and push-pin that retain the filler neck to the body.
  5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  6. Remove the fuel filler tube ground strap bolt.
  7. Loosen the fuel fill hose to fuel fill pipe clamp.
  8. Disconnect the fuel fill hose from the fuel fill pipe.
  9. Remove the fuel fill pipe assembly.
  1. Install the fuel fill pipe to the fuel fill hose.
  2. Align the fuel fill pipe to the fuel fill pipe housing. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  3. Install the fuel filler tube ground strap bolt. Tighten: Tighten the fuel filler tube ground strap bolt to 8 N.m (70 lb in).
  4. Lower the vehicle.
  5. Install the fuel fill pipe housing bolts and push-pin. Tighten: Tighten the fuel fill pipe housing bolts to 6 N.m (53 lb in).
  6. Refill the fuel tank.
  7. Install the fuel filler cap.
  1. Clean all the fuel pipe and hose connections and the surrounding areas before disconnecting in order to avoid contamination of the fuel system.
  2. Remove the fuel filler cap.
  3. Drain the fuel below the level of the fuel tank fill hose. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the 2 retaining bolts and push-pin that retain the filler neck to the body.
  5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  6. Remove the fuel filler tube ground strap bolt.
  7. Loosen the fuel fill hose to fuel fill pipe clamp.
  8. Disconnect the fuel fill hose from the fuel fill pipe.
  9. Remove the fuel fill pipe assembly.
  1. Install the fuel fill pipe to the fuel fill hose.
  2. Align the fuel fill pipe to the fuel fill pipe housing. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  3. Install the fuel filler tube ground strap bolt. Tighten: Tighten the fuel filler tube ground strap bolt to 8 N.m (70 lb in).
  4. Lower the vehicle.
  5. Install the fuel fill pipe housing bolts and push-pin. Tighten: Tighten the fuel fill pipe housing bolts to 6 N.m (53 lb in).
  6. Refill the fuel tank.
  7. Install the fuel filler cap.
  1. Clean all the fuel pipe and hose connections and the surrounding areas before disconnecting in order to avoid contamination of the fuel system.
  2. Remove the fuel filler cap.
  3. Drain the fuel below the level of the fuel tank fill hose. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the 2 retaining bolts and push-pin that retain the filler neck to the body.
  5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  6. Remove the fuel filler tube ground strap bolt.
  7. Loosen the fuel fill hose to fuel fill pipe clamp.
  8. Disconnect the fuel fill hose from the fuel fill pipe.
  9. Remove the fuel fill pipe assembly.
  1. Install the fuel fill pipe to the fuel fill hose.
  2. Align the fuel fill pipe to the fuel fill pipe housing. Tighten: Tighten the fuel fill hose clamp to 2.75 N.m (24 lb in).
  3. Install the fuel filler tube ground strap bolt. Tighten: Tighten the fuel filler tube ground strap bolt to 8 N.m (70 lb in).
  4. Lower the vehicle.
  5. Install the fuel fill pipe housing bolts and push-pin. Tighten: Tighten the fuel fill pipe housing bolts to 6 N.m (53 lb in).
  6. Refill the fuel tank.
  7. Install the fuel filler cap.

J 39765 Fuel Sender Lock Nut Wrench. See Special Tools & Equipment .

  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the retaining ring from the fuel sender assembly using the J 39765 . See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Remove the fuel sender assembly and the seal. Discard the seal.
  7. Clean the fuel sender sealing surfaces.
  1. Install the new seal on the fuel tank.
  2. Install the fuel sender assembly into the fuel tank.
  3. Install the retaining ring to the fuel sender assembly using the J 39765 . See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  4. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Refill the fuel tank.
  6. Tighten the fuel filler cap.
  7. Connect the negative battery cable.
  8. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Disconnect the fuel feed and return pipes (3) from the engine compartment fuel pipes (4).
  4. Remove the fuel pipes from the bellhousing stud retainer clip (2).
  5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  6. Disconnect the fuel feed pipe (5) at the fuel filter.
  7. Disconnect the chassis fuel return pipe (4) at the rear fuel return pipe (3).
  8. Remove the fuel pipe retaining clips (1). Note the location of the retaining clips for installation.
  9. Remove the fuel feed and return pipes (2).
  1. Position the fuel feed and return pipes (2) in the vehicle.
  2. Install the fuel pipe retaining clips (1). Tighten: Tighten the bolts to 12 N.m (106 lb in).
  3. Connect the chassis fuel return pipe (4) to the rear fuel return pipe (3).
  4. Connect the fuel feed pipe (5) to the fuel filter.
  5. Lower the vehicle.
  6. Connect the fuel feed and return pipes (3) to the engine compartment fuel pipes (4). Ensure the O-rings are in place Tighten: Tighten the fuel pipe fittings to 27 N.m (20 lb ft) using a backup wrench.
  7. Install the fuel pipes to the retainer clip (2). Tighten: Tighten the fuel pipe retainer clip nut to 28 N.m (21 lb ft).
  8. Tighten the fuel filler cap.
  9. Connect the negative battery cable.
  10. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  11. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  5. Disconnect the fuel feed pipe the fuel filter.
  6. Disconnect the chassis fuel return pipe the rear fuel return pipe.
  7. Disconnect the chassis fuel feed and return pipes at the rear fuel feed and return pipes (2).
  8. Remove the fuel pipe retaining clips (1).
  9. Remove the fuel feed and return pipes.
  1. Install the fuel feed and return pipes and the fuel pipe retaining clips (1) to the frame rail. Tighten: Tighten the bolts to 12 N.m (106 lb in).
  2. Connect the chassis fuel feed and return pipes to the rear fuel feed and return pipes (2).
  3. Connect the chassis fuel return pipe to the rear fuel return pipe (2).
  4. Connect the fuel feed pipe to the fuel filter.
  5. Lower the vehicle.
  6. Refill the fuel tank.
  7. Tighten the fuel filler cap.
  8. Connect the negative battery cable.
  9. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Disconnect the fuel feed pipe at the fuel filter.
  6. Disconnect the chassis fuel return pipe (4) at the rear fuel return pipe (2).
  7. Remove the fuel pipe retaining clips (1).
  8. Remove the fuel feed and return pipes.
  1. Install the fuel feed and return pipes and the fuel pipe retaining clips (1). Tighten: Tighten the bolts to 12 N.m (106 lb in).
  2. Connect the chassis fuel return pipe to the rear fuel return pipe.
  3. Connect the fuel feed pipe to the fuel filter.
  4. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Lower the vehicle.
  6. Refill the fuel tank.
  7. Tighten the fuel filler cap.
  8. Connect the negative battery cable.
  9. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  4. Loosen the fuel and evaporative emissions (EVAP) pipe retainer (2) nut at the bellhousing stud.
  5. Disconnect the chassis fuel feed and return pipes (3) at the engine compartment fuel feed and return pipes (4).
  6. Remove the injector fuel inlet and outlet pipe retainer nuts.
  7. Remove the injector fuel inlet and the outlet pipe retainer.
  8. Remove the retaining bolt from the rear fuel pipe bracket.
  9. Pull straight up on the fuel pipes in order to remove the fuel pipes from the injector assembly.
  10. Remove the O-ring seals from both ends of the fuel feed and return pipes.
  11. Discard the O-ring seals.
  1. Assemble the new O-rings into the inlet and outlet of the fuel injector assembly.
  2. Apply a few drops of clean engine oil to the male tube ends.
  3. Install the fuel feed and return pipes to the injector assembly.
  4. Install the fuel pipe retainer and the attaching nuts.
  5. Install the retaining bolt to the rear fuel pipe bracket. Tighten: Tighten the bracket bolt to 6 N.m (53 lb in). Tighten the retainer nuts to 3 N.m (27 lb in).
  6. Install the new O-ring seals on the engine fuel feed and the return pipes.
  7. Install the chassis fuel feed and return pipes (3) to the engine compartment fuel feed and return pipes (4). Tighten: Tighten the fuel pipe nuts to 27 N.m (20 lb ft).
  8. Install the retainer nut to the fuel and EVAP pipe. Tighten: Tighten the retainer nut to 28 N.m (21 lb ft).
  9. Tighten the fuel filler cap.
  10. Connect the negative battery cable.
  11. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  12. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  5. Disconnect the fuel feed pipe at the fuel filter.
  6. Disconnect the chassis fuel return pipe at the rear fuel return pipe.
  7. Disconnect the chassis fuel feed and return pipes at the rear fuel feed and return pipes.
  8. Remove the fuel pipe retaining clips.
  9. Remove the fuel feed and return pipes.
  1. Install the fuel feed and return pipes and the fuel pipe retaining clips (2) to the frame rail (1). Tighten: Tighten the bolts to 12 N.m (106 lb in).
  2. Connect the chassis fuel feed and return pipes to the rear fuel feed and return pipes (2).
  3. Connect the chassis fuel return pipe to the rear fuel return pipe.
  4. Connect the fuel feed pipe to the fuel filter.
  5. Lower the vehicle.
  6. Refill the fuel tank.
  7. Tighten the fuel filler cap.
  8. Connect the negative battery cable.
  9. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition switch. Inspect for fuel leaks.
  10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Disconnect the fuel feed and return pipes (3) from the engine compartment fuel pipes (4).
  4. Remove the fuel pipes from the bellhousing stud retainer clip.
  5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  6. Disconnect the fuel feed pipe at the fuel filter.
  7. Disconnect the chassis fuel return pipe at the rear fuel return pipe.
  8. Remove the fuel pipe retaining clips. Note the location of the retaining clips for installation.
  9. Remove the fuel feed and return pipes.
  1. Position the fuel feed and return pipes in the vehicle.
  2. Install the fuel pipe retaining clips (1). Tighten: Tighten the clips to 12 N.m (106 lb in).
  3. Connect the chassis fuel return pipe (4) to the rear fuel return pipe.
  4. Connect the fuel feed pipe (5) to the fuel filter.
  5. Lower the vehicle.
  6. Install the fuel feed and return pipes to the engine compartment fuel pipes. Tighten: Tighten the fuel pipe fittings to 27 N.m (20 lb ft).
  7. Install the fuel pipes to the retainer clip. Tighten: Tighten the fuel pipe retainer clip nut to 28 N.m (21 lb ft).
  8. Tighten the fuel filler cap.
  9. Connect the negative battery cable.
  10. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  11. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Disconnect the fuel feed pipe at the fuel filter.
  6. Disconnect the chassis fuel return pipe at the rear fuel return pipe.
  7. Remove the fuel pipe retaining clips.
  8. Remove the fuel feed and return pipes.
  1. Install the fuel feed and return pipes and the fuel pipe retaining clips (1). Tighten: Tighten the bolts to 12 N.m (106 lb in).
  2. Connect the chassis fuel return pipe to the rear fuel return pipe.
  3. Connect the fuel feed pipe to the fuel filter.
  4. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Lower the vehicle.
  6. Refill the fuel tank.
  7. Tighten the fuel filler cap.
  8. Connect the negative battery cable.
  9. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel feed and return pipes (6) from the fuel sender (1), the fuel filter, and the retaining clips.
  1. Install the fuel feed and return pipes (6) to the fuel sender (1), the fuel filter, and the retaining clips.
  2. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Lower the vehicle.
  4. Refill the fuel tank.
  5. Tighten the fuel filler cap.
  6. Connect the negative battery cable.
  7. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel feed and return pipes (4) from the fuel sender (2).
  1. Install the fuel feed and return pipes (4) to the fuel sender (2).
  2. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Lower the vehicle.
  4. Refill the fuel tank.
  5. Tighten the fuel filler cap.
  6. Connect the negative battery cable.
  7. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

Fuel System Cleaning

  1. Disconnect the negative battery cable.
  2. Relieve fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Drain fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-tank-draining-procedure) .
  4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  5. Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Inspect the fuel strainer. Replace a contaminated strainer and inspect the fuel pump.
  7. Inspect the fuel pump inlet for dirt and debris. Replace the fuel pump if you find dirt or debris in the fuel pump inlet.
  8. Flush the fuel tank with hot water.
  9. Pour the water out of the fuel sender assembly opening.
  10. Rock the tank to ensure that removal of the water from the tank is complete.
  11. Inspect the fuel filter for contamination.
  12. Replace the fuel filter if the filter is plugged. Refer to «Fuel Filter Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Filter Replacement (Cutaway Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  13. Clean the fuel lines by applying air pressure in the opposite direction of the fuel flow.
  14. Install the fuel sender assembly with a new seal into the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  15. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  16. Inspect for leaks: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) Interior Trim.
  2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__fuel-pressure-relief-procedure) .
  3. Use a standard valve core tool in order to remove the valve core (2).
  1. Use a standard valve core tool in order to install a new valve core (2).
  2. Tighten the fuel filler cap.
  3. Connect the negative battery cable.
  4. Inspect for leaks. Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition for 2 seconds. Inspect for fuel leaks.
  5. Install the fuel pressure connection valve cap (3).
  6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) Interior Trim.
IMPORTANTAn 8-digit part identification number is on a mylar label affixed to the fuel meter body. Refer to this number if servicing or part replacement is required.
  1. Remove the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) in Engine Mechanical - 4.3L.
  2. Remove and discard the fuel meter body seal.
  3. Before removal, clean the fuel meter body with a spray type engine cleaner, such as GM X-30A, or equivalent, if necessary. Follow the package instructions. Do not soak the fuel meter body in liquid cleaning solvent.
  4. Remove the injectors from the lower intake manifold bores. Lightly pull on the injector tube and using a small pocket screwdriver, remove the injector from the manifold.
  5. Remove the MFI (multi-port flexible injection) fuel meter body from the MFI bracket.
IMPORTANTThe number 3 fuel tube must be positioned behind the number 1 fuel tube to eliminate interference with the upper intake manifold when installed.
  1. Position the fuel tubes of the MFI fuel meter body in the forward position.
  2. Install the MFI fuel meter body into the fuel meter body bracket on the lower intake manifold. Push down firmly to lock the fuel meter body into the fuel meter body bracket.
  3. Insert the injectors in the following sequence into the correct injector bore in the lower manifold. Number 3 Number 5 Number 1 Number 2 Number 4 Number 6
  4. Insure the electrical connectors on the injectors are positioned so that they do not interfere with each other and are pointing towards the center of the intake manifold. Rotate the electrical connectors inboard if necessary.
  5. Lubricate the upper intake manifold O-ring on the fuel meter body with clean engine oil.
  6. Install the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) in Engine Mechanical - 4.3L.
  7. Tighten the fuel fill cap.
  8. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
  9. Test for fuel leaks using the following procedure: Turn the ignition ON, with the engine OFF, for 2 seconds. Turn the ignition OFF for 10 seconds. Turn the ignition ON, with the engine OFF. Inspect for fuel leaks.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) Interior Trim.
  2. Remove the upper intake manifold assembly. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) in Engine Mechanical - 4.3L.
  3. Remove the fuel pressure regulator retainer clip (13).
  4. Pull and twist the fuel pressure regulator (14) in order to remove the fuel pressure regulator from the fuel pressure regulator housing using a shop towel to catch any spilled fuel.
  5. Remove the regulator seal lower O-ring (18).
  6. Remove the regulator assembly filter (17).
  7. Remove the regulator seal upper O-ring (16).
  8. Remove the regulator seal backup ring (15).
  9. Cover the fuel pressure regulator housing to prevent contamination from entering the fuel system.
  10. Discard the O-rings.
IMPORTANTIf the fuel pressure regulator is to be reinstalled, inspect the filter screen for contamination. If the filter screen is contaminated, replace the regulator.
  1. Lubricate the new O-rings with clean engine oil.
  2. Install the regulator seal backup ring (15).
  3. Install the regulator seal upper O-ring (16).
  4. Install the regulator assembly filter (17).
  5. Install the regulator seal lower O-ring (18).
  6. Assemble the regulator with the vacuum tube pointing down into the regulator retainer clip.
  7. Install the fuel pressure regulator retainer clip (13).
  8. Install the upper manifold assembly. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) in Engine Mechanical-4.3L.
  9. Tighten the fuel filler cap.
  10. Connect the negative battery cable.
  11. Inspect for leaks. Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
  12. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Remove the fuel meter body assembly. Refer to «Fuel Meter Body Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  2. Remove the injector assembly retainer (11) and the injector retainer lock nuts (10).
  3. While pulling the poppet nozzle tube downward, push with a small tip punch down between the injector terminals until the injector is removed.
IMPORTANTEach injector is calibrated for a specific flow rate. Order the correct injector for the application being serviced when replacing the fuel injectors.
  1. Lubricate the new injector O-ring seals with clean engine oil.
  2. Install the O-rings on the injector assembly (2).
  3. Install the fuel injector assembly (12) into the injector socket.
  4. Install the injector assembly retainer (11) and the injector retainer lock nuts (10). Tighten: Tighten the lock nuts to 3.0 N.m (27 lb in).
  5. Install the fuel meter body assembly. Refer to «Fuel Meter Body Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .

Fuel Injector Cleaning Procedure

Tools Required

  1. J 44466-12 CSFI Fuel Metering Body Jumper Block
  2. J 44466-13 Screws
  3. J 44466-11 IAFM Fuel Transfer Tube Recycling Block
  4. J 41413 EVAP Pressure and Purge Station
  5. J 44466-10 Regulator and Hose Assembly
  6. J 39021 Fuel Injector Coil and Balance Tester. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  7. J 39021-210 Injector Tester Adapter Box. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  8. J 39021-301 V6 Fuel Injector Test Adapter. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  9. J 38500-A Fuel Injector Cleaner
  1. Loosen the fuel fill cap to relieve vapor pressure in the fuel tank.
  2. Remove the positive crankcase ventilation (PCV) clean air tube from air inlet duct and set aside.
  3. Remove the resonator and air inlet duct from throttle body.
  4. Remove the brake booster vacuum hose and connector from intake manifold.
  5. Remove the electrical connector from the central sequential fuel injection (CSFI) fuel metering body.
  6. Remove the spark plug wires from 1, 3 and 5 from the distributor cap.
  7. Remove the fuel line bolt (4) at the rear of intake manifold.
  8. Relieve the fuel system pressure.
  9. Remove the nuts (1) and clamp (2) from the fuel pipe.
  10. Remove fuel pipes from the metering body.
  11. Install the J 44466-12 (2) and the J 44466-13 (1) to the metering body and tighten.
  12. Install the J 44466-11 (4), clamp (2) and J 44466-13 (1) to the fuel pipe and tighten.
  13. Obtain the J 41413 , close the valve (2) on the tank (3), and remove the regulator assembly.
  14. Install the J 44466-10 (5) to the J 41413 tank (3)
  15. Connect the J 44466-10 hose (1) to the J 44466-12 (3).
  16. Install the J 39021 and J 39021-210 and J 39021-301 (4) to the metering body electrical connector. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  17. Adjust the amperage selector switch on J 39021 to 0.5 amps. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  18. Open the valve (2) on the tank (3).
  19. Open the valve (4) on the J 44466-10 to pressurize the fuel system. Then close valve (4) before firing injectors. IMPORTANT: The minimum pressure required on the gage (6) is 150 psi. If 150 psi is not obtained, the tank (3) must be refilled prior to performing this procedure.
  20. Fire one injector using the J 39021 . See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) . Observe a pressure drop on the gage (6) and verify the injector/poppet valve operation. An injector/poppet that is stuck and not operational will have no pressure drop on the gage. If an injector remains stuck, repeat the procedure multiple times (as required) until the injector is operational.
  21. Repeat steps 19 and 20 for each individual injector to verify that all injector/poppet valve assemblies are unstuck and functional.
  22. Shut off the pressure valve (2) on the tank (3) of the J 41413 .
  23. Bleed off the pressure at the J 44466-10 .
  24. Install the PCV fresh air tube to the air inlet duct.
  25. Disconnect and remove the J 44466-10 (1) from the J 44466-12 (3) and the J 41413 .
  26. Remove the J 39021-301 , J 39021-210 and J 39021 from the metering body. See «Special Tools & Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  27. Install the vehicle electrical connector to the metering body.
  28. Install brake booster vacuum hose and connector to the intake manifold.
  29. Install ignition wires 1, 3, and 5 to the distributor cap.
  30. Install the resonator and air intake duct to the throttle body and hand tighten wing nut.
  31. Obtain J 38500-A (2).
  32. Remove the canister top and add top engine cleaner GM P/N 1050002 (Canadian P/N 992872) to the canister.
  33. Fill the remainder of the canister with regular unleaded gasoline and install the canister top.
  34. Suspend J 38500-A from a convenient underhood location.
  35. Connect the hose from J 38500-A (1) to the service port on the J 44466-12 (3).
  36. Open valve (3) at the bottom of J 38500-A .
  37. Connect a shop air source to the fitting at the top of J 38500-A and adjust the regulator (1) to 75 psi.
  38. Let the vehicle run at idle until the canister is empty and the vehicle stalls.
  39. Remove the shop air supply from J 38500-A .
  40. Depressurize the J 38500-A .
  41. Disconnect the J 38500-A hose from the J 44466-12 .
  42. Remove the PCV clean air tube from the air inlet duct and set aside.
  43. Remove the resonator and air inlet duct from the throttle body and set aside.
  44. Remove ignition wires 1, 3, and 5 from the distributor cap.
  45. Remove brake booster vacuum hose and connector from the intake manifold.
  46. Bleed the residual pressure from J 44466-12 .
  47. Remove J 44466-13 (1) and J 44466-12 (2) from the metering body.
  48. Remove J 44466-13 (1), clamp (2) and J 44466-11 (4) from the fuel pipe (3).
  49. Install the fuel pipe (3) to the metering body.
  50. Install the clamp (2) and nuts (1). Tighten: Tighten the nuts to 3 N.m (27 lb ft).
  51. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489), or equivalent to the threads of the fuel pipe bolt (4).
  52. Install the fuel pipe bolt. Tighten: Tighten the bolt to 6 N.m (53 lb ft).
  53. Install the brake booster vacuum hose and connector to the intake manifold.
  54. Install the resonator and air inlet duct to the throttle body.
  55. Install the PCV clean air tube to the inlet duct.
  56. Install brake booster vacuum hose and connector to the intake manifold.
  57. Install ignition wires 1, 3, and 5 to the distributor cap.
  58. Add 1 ounce of port fuel injector cleaner GM P/N 12345104 (Canadian P/N 12345515), or equivalent to the vehicle fuel tank for each gallon of gasoline estimated to be in the tank. IMPORTANT: Instruct the customer to add the remainder of the bottle of port fuel injector cleaner to the vehicle fuel tank at the next fill up.
  59. Hand tighten the fuel tank filler cap.
  60. Start the vehicle and check for fuel leaks.
  61. Using a Tech II scan tool, check for any stored Powertrain DTC codes. Clear codes as required.
  62. Disconnect Tech II scan tool. IMPORTANT: Advise the customer to change brands of fuel.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Disconnect the
  3. Disconnect the purge valve electrical connector.
  4. Remove the purge valve mounting nuts.
  5. Remove the engine wiring harness bracket from the mounting stud.
  6. Remove the purge valve from the intake manifold.
  1. Install the purge valve to the intake manifold.
  2. Install the engine wiring harness bracket to the mounting stud.
  3. Install the purge valve mounting nuts. Tighten: Tighten the nuts to 12 N.m (106 lb in).
  4. Connect the purge valve electrical connector.
  5. Connect the EVAP purge pipe.
  6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the electrical connector from the EVAP vent valve.
  3. Disconnect the canister vent hose.
  4. Bend back the tang on the bracket.
  5. Slide the EVAP vent valve off the bracket.
  1. Slide the EVAP vent valve onto the bracket.
  2. Connect the canister vent hose.
  3. Connect the electrical connector to the EVAP vent valve.
  4. Lower the vehicle.
IMPORTANTWhen replacing the evaporative emission (EVAP) pipe, always replace the pipe with original equipment or parts that meet the GM specifications for this part. The replacement pipe must have the same type of fittings as the original pipe in order to ensure the integrity of the connection.
  1. Clean the pipe connections and the surrounding areas before disconnecting in order to avoid possible contamination of the EVAP system.
  2. Disconnect the engine compartment EVAP pipe at the EVAP canister purge valve.
  3. Disconnect the engine compartment EVAP pipe (1) at the chassis EVAP pipe (2).
  4. Remove the EVAP pipe from the engine.
  5. Cap the EVAP canister purge valve and the chassis EVAP pipe in order to prevent possible EVAP system contamination.
  1. Remove the caps from the EVAP canister purge valve and the chassis EVAP pipe.
  2. Install the EVAP pipe on the engine.
  3. Connect the engine compartment EVAP pipe (1) to the chassis EVAP pipe (2).
  4. Connect the engine compartment EVAP pipe at the EVAP canister purge valve.
IMPORTANTWhen replacing the evaporative emission (EVAP) pipe, always replace the pipe with original equipment or parts that meet the GM specifications for this part. The replacement pipe must have the same type of fittings as the original pipe in order to ensure the integrity of the connection.
  1. Remove the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  2. Disconnect the rear EVAP vapor pipe (1) from the fuel sender (2), the fuel tank roll over valve (3), and the fuel tank clips (6).
  3. Remove the EVAP vapor pipe from the fuel tank.
  4. Cap the fuel sender EVAP pipe and the fuel tank roll over valve.
  1. Remove the caps from the fuel sender EVAP pipe and the fuel tank roll over valve.
  2. Position the EVAP vapor pipe on the fuel tank.
  3. Connect the EVAP vapor pipe (1) to the fuel sender (2), the fuel tank roll over valve (3), and the fuel tank clips (6).
  4. Install the fuel tank. Refer to «Fuel Tank Replacement (Cutaway Van Side Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Passenger/Cargo Van)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) or «Fuel Tank Replacement (Cutaway Van Rear Tank)»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
IMPORTANTWhen replacing the evaporative emission (EVAP) pipe, always replace the pipe with original equipment or parts that meet the GM specifications for this part. The replacement pipe must have the same type of fittings as the original pipe in order to ensure the integrity of the connection.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Clean all the EVAP pipe connections and the surrounding areas before disconnecting the pipes in order to avoid possible contamination of the EVAP system.
  3. Disconnect the engine compartment EVAP pipe (1) from the chassis EVAP pipe (2).
  4. Cap the engine compartment EVAP pipe.
  5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  6. Remove the EVAP pipe from the bellhousing stud clip.
  7. Remove the EVAP pipe from the transmission bracket clip.
  8. Remove the EVAP pipe from the transfer case bracket clip, AWD drive only.
  9. Disconnect the rear EVAP purge pipe (3) from the chassis EVAP purge pipe (2).
  10. Cap the rear EVAP purge pipe (3).
  11. Note the position of the EVAP pipe for aid in installation.
  12. Remove the EVAP pipe from the retaining clips (1).
  13. Remove the EVAP pipe.
  1. Install the EVAP pipe into the retaining clips (1).
  2. Remove the cap from the rear EVAP pipe.
  3. Connect the rear EVAP purge pipe (3) to the chassis EVAP purge pipe (2).
  4. Install the EVAP pipe into the transfer case bracket clip, AWD drive only.
  5. Install the EVAP pipe into the transmission bracket clip.
  6. Install the EVAP pipe into the bellhousing stud clip (3).
  7. Lower the vehicle.
  8. Remove the cap from the engine compartment EVAP pipe.
  9. Connect the engine compartment EVAP pipe (1) to the chassis EVAP pipe (2).
  10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the vent hose from the canister.
  3. Disconnect the chassis EVAP purge pipe from the EVAP canister.
  4. Disconnect the fuel tank EVAP pipe from the canister.
  5. Remove the EVAP canister from the EVAP canister bracket.
  1. Install the EVAP canister to the EVAP canister bracket.
  2. Connect the fuel tank EVAP pipe to the canister.
  3. Connect the chassis EVAP purge pipe to the EVAP canister.
  4. Connect the vent hose to the canister.
  5. Lower the vehicle.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the vent hose from the canister.
  3. Disconnect the chassis EVAP purge pipe from the EVAP canister.
  4. Disconnect the fuel tank EVAP pipe from the canister.
  5. Remove the EVAP canister from the EVAP Canister bracket.
  1. Connect the fuel tank EVAP pipe to the canister.
  2. Connect the chassis EVAP purge pipe to the EVAP canister.
  3. Connect the vent hose to the canister.
  4. Install the EVAP canister to the EVAP Canister bracket.
  5. Install the EVAP canister bracket bolt. Tighten: Tighten the bolt to 12 N.m (106 lb in).
  6. Lower the vehicle.

Distributor Inspection

  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Inspect the cap for cracks, tiny holes or carbon tracks between the cap terminal traces. Diagnose the carbon tracks using the following procedure: Remove the cap. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) . Place 1 lead from the DMM on a cap terminal. Use the other lead in order to probe all other terminals and the center carbon ball. Move the base lead to the next terminal. Probe all other leads. Continue this procedure until you test all the secondary terminals. If there are any non-infinite readings, replace the cap.
  3. Inspect the cap for excess build-up of corrosion on the terminals. Scrape clean the terminals. Replace the cap if the corrosion is excessive. Some buildup is normal.
  4. Inspect the rotor segment for excess wear. Replace the rotor if excess looseness in the rotor segment is present.
  5. Inspect the shaft for shaft-to-bushing looseness: Inspect the housing for cracks or damage. Insert the shaft in the housing. If the shaft wobbles, replace the housing assembly.
  6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Disassembly Procedure

  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Align white paint mark on the bottom stem of the distributor, and the pre-drilled indent hole in the bottom of the gear (2).
  3. With the gear in this position, the rotor segment should be positioned as shown for a V6 engine (1). If not, replace the distributor.
  4. Remove the two screws from the rotor.
  5. Remove the rotor.
  6. Note the locating holes that the rotor was removed from: The rotor screw holes (1) The rotor locator pin holes (2)
  7. Line up the square-cut hole in the vane wheel with the camshaft position (CMP) sensor.
  8. Remove the two screws that hold the camshaft position (CMP) sensor.
  9. Discard the screws.
  10. Remove the CMP sensor.
  11. Note the dimple located below the roll pin hole on one side of the gear. The dimple will be used to properly orient the gear onto the shaft during reassembly.
  12. Support the distributor drive gear in a V-block or similar fixture.
  13. Drive out the roll pin with a suitable punch.
  14. Remove the driven gear from the distributor shaft.
  15. Remove the round washer.
  16. Remove the tang washer.
  17. Remove the shim washer (1).
  18. Remove the old oil seal.

Assembly Procedure

  1. Line up the square-cut hole in the vane wheel for the camshaft position (CMP) sensor.
  2. Insert the sensor into the housing.
  3. Install two new screws for the camshaft position (CMP) sensor. Tighten: Tighten the screws to 2.2 N.m (20 lb in).
  4. Identify the correct rotor mounting position: At the rotor screw holes (1) At the rotor locator pin holes (2)
  5. Install the distributor rotor according to the index marks.
  6. Install two rotor hold down screws. Tighten: Tighten the screws to 1.9 N.m (17 lb in).
  7. Install the shim washer (1) on the bottom of the distributor shaft.
  8. Install the tang washer.
  9. Install the round washer.
  10. Install the driven gear according to the index marks.
  11. Align the rotor segment as shown for a V6 engine (1) or V8 engine (2).
  12. Install the gear and align white paint mark on the bottom stem of the distributor, and the pre-drilled indent hole in the bottom of the gear (3).
  13. Check to see If the driven gear is installed incorrectly, the dimple will be approximately 180 degrees opposite the rotor segment when it is installed in the distributor.
  14. Support the distributor drive gear in a V-block or similar fixture.
  15. Install the roll pin with a suitable punch and hammer in order to hold the driven gear in the correct position.
  16. Install the new oil seal under the mounting flange of the distributor base.
  17. Install the distributor.
  18. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Note. There are two procedures available to install the distributor. Use Installation Procedure 1 when the crankshaft has NOT been rotated from the original position. Use Installation Procedure 2 when any of the following components are removed. The intake manifold The cylinder head The camshaft The timing chain or sprockets The complete engine If the malfunction indicator lamp (MIL) turns on and DTC P1345 sets after installing the distributor, this indicates an incorrectly installed distributor. Engine damage or distributor damage may occur. Use Procedure 2 in order to install the distributor.

  1. Turn OFF the ignition.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Remove air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  4. Remove the air intake resonator assembly.
  5. Remove the spark plug wires from the distributor cap. Twist each spark plug wire boot 1/2 turn. Pull only on the wire boot in order to remove the wire from the distributor cap.
  6. Remove the electrical connector from the base of the distributor.
  7. Remove the 2 screws that retain the distributor cap to the housing.
  8. Discard the screws.
  9. Remove the distributor cap from the housing.
  10. Use a grease pencil in order to mark the position of the rotor in relation to the distributor housing (1).
  11. Mark the distributor housing and the intake manifold with the grease pencil.
  12. As the distributor is being removed from the engine, watch the rotor move in a counter-clockwise direction about 42 degrees. This will appear as slightly more than one clock position.
  13. Note the position of the rotor segment.
  14. Place a second mark on the base of the distributor (2). This will aid in achieving the proper rotor alignment during the distributor installation.
  15. Remove the mounting clamp hold-down bolt.
  16. Remove the distributor.

Installation Procedure 1

  1. If installing a new distributor assembly, place 2 marks on the new distributor housing in the same location as the marks on the original housing.
  2. Remove the new distributor cap, if necessary.
  3. Align the rotor with the second mark (2).
  4. Guide the distributor into the engine.
  5. Align the hole in the distributor hold-down base over the mounting hole in the intake manifold.
  6. As the distributor is being installed, observe the rotor moving in a clockwise direction about 42 degrees.
  7. Once the distributor is completely seated, the rotor segment should be aligned with the mark on the distributor base (1). If the rotor segment is not aligned with the mark, the driven gear teeth and the camshaft have meshed one or more teeth out of alignment. In order to correct this condition, remove and reinstall the distributor.
  8. Install the distributor mounting clamp bolt. Tighten: Tighten the bolt to 25 N.m (18 lb ft).
  9. Install the distributor cap.
  10. Install the new distributor cap screws. Tighten: Tighten the screws to 2.4 N.m (21 lb in).
  11. Install the electrical connector to the distributor.
  12. Install the spark plug wires to the distributor cap.
  13. Install the ignition coil wire. Note the correct orientation of the wire boot.
  14. Refer to Installation Procedure 2 if the malfunction indicator lamp illuminates after installing the distributor.
  15. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Installation Procedure 2

  1. Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover and the number 1 piston is at TDC of the compression stroke.
  2. Align the white paint mark on the bottom stem of the distributor and the pre-drilled indent hole in the bottom of the gear (3).
  3. With the gear in this position, the rotor segment should be positioned as shown for a V6 engine (1). The alignment will not be exact. If the driven gear is installed incorrectly, the dimple will be approximately 180 degrees opposite of the rotor segment when installed in the distributor.
  4. Use a long screw driver in order to align the oil pump drive shaft to the drive tab of the distributor.
  5. Guide the distributor into the engine. Ensure the flat portion of the distributor housing is facing toward the front of the engine.
  6. Once the distributor is fully seated, the rotor segment should be aligned with the pointer cast into the distributor base. If the rotor segment does not come within a few degrees of the pointer, repeat the procedure in order to achieve the proper alignment.
  7. Install the distributor mounting clamp bolt. Tighten: Tighten the bolt to 25 N.m (18 lb ft).
  8. Install the distributor cap.
  9. Install the new distributor cap screws. Tighten: Tighten the screws to 2.4 N.m (21 lb in).
  10. Install the electrical connector to the distributor.
  11. Install the spark plug wires to the distributor cap.
  12. Install the ignition coil wire. Note the correct orientation of the wire boot.
  13. Repeat Installation Procedure 2 if the malfunction indicator lamp illuminates after installing the distributor.
  14. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Disconnect the ignition coil electrical connectors.
  3. Remove the ignition coil wire to the distributor.
  4. Remove the accelerator cable bracket.
  5. Remove the studs holding the bracket and the ignition coil to the intake manifold.
  6. Remove the bracket and the ignition coil.
  7. Drill and punch out the two rivets holding the ignition coil to the bracket.
  8. Remove the ignition coil from the bracket.
  1. Install the ignition coil to the bracket with the 2 screws.
  2. Install the ignition coil and the bracket to the intake manifold with studs. Tighten: Tighten the studs to 11 N.m (97 lb in).
  3. Install the accelerator control bracket. Tighten: Tighten the accelerator control cable bracket nuts and studs to 12 N.m (106 lb in).
  4. Install the ignition coil wire. The wire must not touch anything like the dip stick. Rubbing will make a ground or short after time of use.
  5. Install the electrical connectors.
  6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Disconnect the electrical connector (3).
  3. Remove the screws (4) holding the ignition control module (2) and the heat sink (1) to the bracket.
  4. Remove the ignition control module and the heat sink.
  1. Install the ignition control module (2) and the heat sink (1) on the bracket with the screws (4). Tighten: Tighten the screws to 3.5 N.m (31 lb in).
  2. Reconnect the electrical connectors (3).
  3. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Spark Plug Wire Inspection

Spark plug wire integrity is vital for proper engine operation. A thorough inspection will be necessary to accurately identify conditions that may affect engine operation. Inspect for the following conditions

  1. Correct routing of the spark plug wires Incorrect routing may cause cross-firing.
  2. Any signs of cracks or splits in the wires.
  3. Inspect each boot for the following conditions: Tearing Piercing Arcing Carbon tracking Corroded terminal

If corrosion, carbon tracking or arcing are indicated on a spark plug wire boot or on a terminal, replace the wire and the component connected to the wire.

  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Disconnect the spark plug wire at each spark plug. Twist the boots 1/2 turn before removing the boots. Pull only on the boot or use a tool designed for this purpose in order to remove the wire from each spark plug.
  3. Disconnect the spark plug wire from the distributor. Twist each spark plug boot 1/2 turn. Pull only on the boot or use a tool designed for this purpose in order to remove the wires from the distributor.
  1. Install the spark plug wires at the distributor.
  2. Install the spark plug wire to each spark plug.
  3. Inspect the wires for proper installation: Push sideways on each boot in order to inspect the seating. Reinstall any loose boot. Wire routings must be kept intact during service and followed exactly when wires have been disconnected or when replacement of the wires is necessary. Failure to route the wires properly can lead to radio ignition noise and crossfiring of the plugs, or shorting of the leads to the ground. Any time the spark plug wires or boots are installed on the spark plugs, new dielectric grease needs to be applied inside the boot.
  4. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Spark Plug Usage

  1. Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. Refer to «Ignition System Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__ignition-system-specifications) for the correct spark plug.
  2. Ensure that the spark plug has the correct heat range. An incorrect heat range causes the following conditions: Spark plug fouling Colder plug Pre-ignition causing spark plug and/or engine damage Hotter plug

Spark Plug Inspection

  1. Inspect the terminal post (1) for damage. Inspect for a bent or broken terminal post (1). Test for a loose terminal post (1) by twisting and pulling the post. The terminal post (1) should NOT move.
  2. Inspect the insulator (2) for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator (2) between the terminal post (1) and ground. Inspect for the following conditions: Inspect the spark plug boot for damage. Inspect the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water. A spark plug boot that is saturated causes arcing to ground.
  3. Inspect the insulator (2) for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes (3, 4).
  4. Inspect for evidence of improper arcing. Measure the gap between the center electrode (4) and the side electrode (3) terminals. An excessively wide electrode gap can prevent correct spark plug operation. Inspect for the correct spark plug torque. Refer to «Ignition System Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__ignition-system-specifications) . Insufficient torque can prevent correct spark plug operation. An over torqued spark plug, causes the insulator (2) to crack. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode (4). Inspect for a broken or worn side electrode (3). Inspect for a broken, worn, or loose center electrode (4) by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode (4) reduces the spark intensity. Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4) reduce or eliminates the gap. Inspect for worn or missing platinum pads on the electrodes (3, 4), if equipped. Inspect for excessive fouling.
  5. Inspect the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation.

Spark Plug Visual Inspection

  1. Normal operation Brown to grayish-tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
  2. Carbon Fouled Dry, fluffy black carbon, or soot caused by the following conditions: Rich fuel mixtures Leaking fuel injectors Excessive fuel pressure Restricted air filter element Incorrect combustion Reduced ignition system voltage output Weak coils Worn ignition wires Incorrect spark plug gap Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
  3. Deposit Fouling Oil, coolant, or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.
  1. Remove the spark plug wires. Refer to «Spark Plug Wire Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  2. Loosen each spark plug 1 or 2 turns.
  3. Brush or air blast away any dirt from around the spark plugs.
  4. Remove the spark plugs 1 at a time. Place each plug in a tray marked with the corresponding cylinder numbers.
  1. Inspect each spark plug gap. Adjust each plug as needed. Specification: Spark plug gap: 1.524 mm (0.060 in).
  2. Hand start the spark plugs in the corresponding cylinders.
  3. Tighten the spark plugs. Tighten: For used heads, tighten the spark plugs to 15 N.m (11 lb ft). For new aluminum heads, tighten the spark plugs to 20 N.m (15 lb ft). For new iron heads, tighten the spark plugs to 30 N.m (22 lb ft).
  4. Install the spark plug wires. Refer to «Spark Plug Wire Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
IMPORTANTPerform the CKP system variation learn procedure whenever the crankshaft position (CKP) sensor is removed or replaced. Refer to CKP System Variation Learn Procedure .
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the CKP sensor harness connector.
  3. Remove the CKP sensor mounting bolt.
  4. Remove the CKP sensor.
IMPORTANTWhen installing the CKP sensor, make sure the sensor is fully seated before tightening the mounting bolt. A poorly seated CKP sensor may perform erratically and may set false DTCs.
  1. Replace the CKP sensor O-ring.
  2. Lubricate the O-ring with clean engine oil before installing the CKP sensor.
  3. Install the CKP sensor.
  4. Install the CKP sensor mounting bolt. Tighten: Tighten the mounting bolt to 8 N.m (71 lb in).
  5. Connect the CKP sensor harness connector.
  6. Lower the vehicle.
  7. Perform the CKP system variation learn procedure. Refer to «CKP System Variation Learn Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction__ckp-system-variation-learn-procedure) .
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Disconnect the spark plug wires and ignition coil wire from the distributor. Refer to «Spark Plug Wire Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Disconnect the camshaft position (CMP) sensor harness connector from the distributor.
  4. Remove the distributor cap screws.
  5. Remove the distributor cap.
  6. Remove the rotor screws.
  7. Remove the rotor.
  8. Align the square slot in the reluctor wheel with the CMP sensor.
  9. Remove the CMP screws.
  10. Remove the CMP sensor.
IMPORTANTDo not use the old cap, CMP sensor, and rotor screws. Use the replacement screws that have been coated with a thread locking compound.
  1. Insert the CMP sensor through the reluctor wheel slot.
  2. Install new CMP mounting screws. Tighten: Tighten the bolts to 2.2 N.m (20 lb in).
  3. Install the rotor onto the reluctor wheel.
  4. Install new rotor screws. Tighten: Tighten the screws to 2 N.m (18 lb in).
  5. Install the distributor cap.
  6. Install new distributor cap screws. Tighten: Tighten the screws to 2.4 N.m (21 lb in).
  7. Connect the CMP sensor harness connector.
  8. Connect the spark plug wires and ignition coil wire. Refer to «Spark Plug Wire Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  9. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

The knock sensor (KS) is located at the top rear of the engine.

  1. Disconnect the negative battery cable.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Disconnect the KS harness connector (3).
  4. Remove the KS bolt (1).
  5. Remove the KS (2).
  1. Install the knock sensor (2) and bolt (1). Tighten: Tighten the knock sensor bolt to 25 N.m (18 lb ft).
  2. Connect the KS harness connector (3).
  3. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
IMPORTANTDo not try to disassemble the linear EGR valve. Service the EGR valve only as a complete assembly.

Scheme 113

Scheme 113
Scheme 113
IMPORTANTCarefully note the position of the linear EGR valve before removal. Do not rotate the linear EGR valve 180 degrees.
  1. Disconnect the negative battery cable.
  2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  3. Remove the linear EGR harness connector.
  4. Remove the bolts attaching the linear EGR valve to the flange.
  5. Remove the linear EGR valve.
  6. Remove the flange gasket.
  7. Clean the EGR valve gasket surface.
  1. Install the new flange gasket.
  2. Install the linear EGR valve.
  3. Install the bolts retaining the linear EGR valve to the flange. Tighten: Tighten the bolts the first pass to 10 N.m (89 lb in). Tighten the bolts the second pass to 25 N.m (18 lb ft).
  4. Install the EGR valve harness connector.
  5. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Connect the negative battery cable.
  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Remove the retaining fastener from the EGR pipe bracket.
  3. Loosen the pipe fittings at both ends of the EGR pipe.
  4. Remove the EGR pipe.
  1. Install the EGR pipe in the proper location and start the pipe fittings by hand. Do not fully tighten at this step.
  2. Ensure that the EGR pipe fittings are correctly lined up on the adaptors to the exhaust and the intake manifolds.
  3. Tighten the EGR pipe fittings to the intake manifold and the exhaust manifold. Tighten: Tighten the fitting to the intake manifold to 25 N.m (18 lb ft). Tighten the fitting to the exhaust manifold to 30 N.m (22 lb ft).
  4. Install the retaining fastener to the EGR pipe bracket. Tighten: Tighten the fastener to 25 N.m (18 lb ft).
  5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Exhaust Gas Recirculation (EGR) System Cleaning

CAUTIONAvoid breathing fumes and swallowing EGR exhaust deposits when removing components for cleaning as bodily injury may result.
  1. Remove the exhaust gas recirculation (EGR) valve. Refer to «Exhaust Gas Recirculation (EGR) Valve Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  2. Press the pintle several times using a pencil eraser or other suitable soft instrument. The pintle should move in and out smoothly. Replace the valve if the valve exhibits tendencies to stick.
  3. Try to rotate the EGR valve electrical connector housing. Repeat for the coil housing. Replace the valve if the valve exhibits any looseness.
  4. Inspect the EGR valve pintle and seat for deposits. Use a cloth or other suitable soft device to remove the deposits. Remove all loose particles. Replace the valve if the deposits are such that the pintle to base interface cannot be cleaned adequately to allow the pintle to seal against the seat.
  5. Remove the EGR pipe. Refer to «Exhaust Gas Recirculation (EGR) Valve Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  6. Clean the passages with a wire brush. Remove all loose particles.
  7. Install the EGR pipe. Refer to «Exhaust Gas Recirculation (EGR) Pipe Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  8. Install the EGR valve. Refer to «Exhaust Gas Recirculation (EGR) Valve Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
  1. Remove the air cleaner assembly end cover clips.
  2. Remove the air cleaner cover from the air cleaner assembly (4).
  3. Remove the element.
  1. Install the element.
  2. Install the cover to the air cleaner assembly (4).
  3. Install the air cleaner assembly end cover clips.
  1. Loosen the duct clamp (1).
  2. Remove the air cleaner assembly bolts (3).
  3. Remove the air cleaner assembly.
  1. Install air cleaner assembly
  2. Install the air cleaner assembly bolts (3). Tighten: Tighten the bolts to 18 N.m (13 lb ft).
  3. Tighten the duct clamp. Tighten: Tighten the clamp to 2 N.m (18 lb in).
  1. Disconnect the negative battery cable.
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Remove the retaining nut (1) from the air cleaner outlet.
  4. Remove the air cleaner outlet duct (2) from the throttle body assembly.
  5. Disconnect the harness connector of the intake air temperature (IAT) sensor.
  6. Loosen the air cleaner outlet duct from the mass air flow (MAF) sensor.
  7. Remove the air cleaner outlet duct.
  1. Install the air cleaner outlet duct to the MAF sensor.
  2. Connect the IAT sensor harness connector.
  3. Install the air cleaner outlet duct (2) on the throttle body assembly.
  4. Tighten the retaining nut (1). Tighten: Tighten the nut 2 N.m (18 lb in).
  5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  6. Connect the negative battery cable.

Powertrain

The powertrain has electronic controls to reduce exhaust emissions while maintaining excellent driveability and fuel economy. The powertrain control module (PCM) is the control center of this system. The PCM monitors numerous engine and vehicle functions. The PCM constantly looks at the information from various sensors and other inputs, and controls the systems that affect vehicle performance and emissions. The PCM also performs the diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. Review the components and wiring diagrams in order to determine which systems are controlled by the PCM.

The following are some of the functions that the PCM controls

  1. The engine fueling
  2. The ignition control (IC)
  3. The knock sensor (KS) system
  4. The evaporative emissions (EVAP) system
  5. The secondary air injection (AIR) system (if equipped)
  6. The exhaust gas recirculation (EGR) system
  7. The automatic transmission functions
  8. The generator
  9. The A/C clutch control
  10. The cooling fan control

Powertrain Control Module Function

The powertrain control module (PCM) constantly looks at the information from various sensors and other inputs and controls systems that affect vehicle performance and emissions. The PCM also performs diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. The input and output devices in the PCM include analog-to-digital converters, signal buffers, counters, and output drivers. The output drivers are electronic switches that complete a ground or voltage circuit when turned on. Most PCM controlled components are operated via output drivers. The PCM monitors these driver circuits for proper operation and, in most cases, can set a DTC corresponding to the controlled device if a problem is detected.

Malfunction Indicator Lamp (MIL) Operation

The malfunction indicator lamp (MIL) is located in the instrument panel cluster. The MIL will display as either SERVICE ENGINE SOON or one of the following symbols when commanded ON

Scheme 114

Scheme 114: Malfunction Indicator Lamp (MIL) Operation
Scheme 114: Malfunction Indicator Lamp (MIL) Operation

Scheme 115

Scheme 115
Scheme 115

The MIL indicates that an emissions related fault has occurred and vehicle service is required.

The following is a list of the modes of operation for the MIL

  1. The MIL illuminates when the ignition is turned ON, with the engine OFF. This is a bulb test to ensure the MIL is able to illuminate.
  2. The MIL turns OFF after the engine is started if a diagnostic fault is not present.
  3. The MIL remains illuminated after the engine is started if the control module detects a fault. A diagnostic trouble code (DTC) is stored any time the control module illuminates the MIL due to an emissions related fault. The MIL turns OFF after three consecutive ignition cycles in which a Test Passed has been reported for the diagnostic test that originally caused the MIL to illuminate.
  4. The MIL flashes if the control module detects a misfire condition which could damage the catalytic converter.
  5. When the MIL is illuminated and the engine stalls, the MIL will remain illuminated as long as the ignition is ON.
  6. When the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition is cycled OFF and then ON.

Trip

A trip is an interval of time during which the diagnostic test runs. A trip may consist of only a key cycle to power up the powertrain control module (PCM), allow the diagnostic to run, then cycle the key off to power down the PCM. A trip may also involve a PCM power up, meeting specific conditions to run the diagnostic test, then powering down the PCM. The definition of a trip depends upon the diagnostic. Some diagnostic tests run only once per trip (i.e., catalyst monitor) while other tests run continuously during each trip (i.e., misfire).

Warm-Up Cycle

The powertrain control module (PCM) uses warm-up cycles to run some diagnostics and to clear any diagnostic trouble codes (DTCs). A warm-up cycle occurs when the engine coolant temperature increases 22°C (40°F) from the start-up temperature. The engine coolant must also achieve a minimum temperature of 71°C (160°F). The PCM counts the number of warm-up cycles in order to clear the malfunction indicator lamp (MIL). The PCM will clear the DTCs when 40 consecutive warm-up cycles occur without a malfunction.

Diagnostic Trouble Codes (DTCs)

The powertrain control module (PCM) is programmed with test routines that test the operation of the various systems the PCM controls. Some tests monitor internal PCM functions. Many tests are run continuously. Other tests run only under specific conditions, referred to as Conditions for Running the DTC. When the vehicle is operating within the conditions for running a particular test, the PCM monitors certain parameters and determines if the values are within an expected range. The parameters and values considered outside the range of normal operation are listed as Conditions for Setting the DTC. When the Conditions for Setting the DTC occur, the PCM executes the Action Taken When the DTC Sets. Some DTCs alert the driver via the malfunction indicator lamp (MIL) or a message. Other DTCs do not trigger a driver warning, but are stored in memory. The PCM also saves data and input parameters when most DTCs are set. This data is stored in the Freeze Frame and/or Failure Records.

The DTCs are categorized by type. The DTC type is determined by the MIL operation and the manner in which the fault data is stored when a particular DTC fails. In some cases there may be exceptions to this structure. Therefore, when diagnosing the system it is important to read the Action Taken When the DTC Sets and the Conditions for Clearing the DTC in the supporting text.

There are different types of DTCs and different actions taken when the DTCs set. Refer to Diagnostic Trouble Code (DTC) Type Definitions for a description of the general characteristics of each DTC type.

DTC Status

When the scan tool displays a DTC, the status of the DTC is also displayed. The following DTC statuses are indicated only when they apply to the DTC that is set.

Fuel System Overview

The fuel tank stores the fuel supply. The electric fuel pump supplies fuel through an in-line fuel filter to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pressure regulator maintains the correct fuel pressure to the fuel injection system. A separate pipe returns unused fuel to the fuel tank.

Fuel Tank

The fuel tank stores the fuel supply. The fuel tank is located in the rear of the vehicle. The fuel tank is held in place by 2 metal straps that attach to the frame. The fuel tank is molded from high-density polyethylene.

Fuel Fill Pipe

The fuel fill pipe has a built-in restrictor in order to prevent refueling with leaded fuel.

Scheme 116

Scheme 116: Fuel Filler Cap
Scheme 116: Fuel Filler Cap

Note. If a fuel tank filler cap requires replacement, use only a fuel tank filler cap with the same features. Failure to use the correct fuel tank filler cap can result in a serious malfunction of the fuel and EVAP system.

The fuel fill pipe has a tethered fuel filler cap. A torque-limiting device prevents the cap from being over-tightened. To install the cap, turn the cap clockwise until you hear audible clicks. This indicates that the cap is correctly torqued and fully seated. A fuel filler cap that is not fully seated may cause a malfunction in the emission system.

Scheme 117

Scheme 117: Fuel Sender Assembly
Scheme 117: Fuel Sender Assembly

The fuel sender assembly consists of the following major components

  1. The fuel level sensor (6)
  2. The fuel tank pressure (FTP) sensor (1)
  3. The fuel pump module (2)
  4. The fuel strainer (3)

Scheme 118

Scheme 118: Fuel Level Sensor
Scheme 118: Fuel Level Sensor

The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the position of the float arm. The control module sends the fuel level information via the Class 2 circuit to the instrument panel cluster (IPC). This information is used for the IPC fuel gage and the low fuel warning indicator, if applicable. The control module also monitors the fuel level input for various diagnostics.

Fuel Pump

The fuel pump is mounted in the fuel sender assembly reservoir. The fuel pump is an electric high-pressure pump. Fuel is pumped to the fuel injection system at a specified flow and pressure. Excess fuel from the fuel injection system returns to the fuel tank through the fuel return pipe. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers. The control module controls the electric fuel pump operation through a fuel pump relay. The fuel pump flex pipe acts to dampen the fuel pulses and noise generated by the fuel pump.

Fuel Strainer

The fuel strainer attaches to the lower end of the fuel sender. The fuel strainer is made of woven plastic. The functions of the fuel strainer are to filter contaminants and to wick fuel. The fuel strainer normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment or contamination.

Scheme 119

Scheme 119: Fuel Filter
Scheme 119: Fuel Filter

The fuel filter is located on the fuel feed pipe, between the fuel pump and the fuel injectors. The paper filter element (2) traps particles in the fuel that may damage the fuel injection system. The filter housing (1) is made to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature.

Fuel Feed and Return Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel injection system. The fuel return pipe carries fuel from the fuel injection system back to the fuel tank. The fuel pipes consist of 2 sections

  1. The rear fuel pipe assemblies are located from the top of the fuel tank to the chassis fuel pipes. The rear fuel pipes are constructed of nylon.
  2. The chassis fuel pipes are located under the vehicle and connect the rear fuel pipes to the fuel injection system. The chassis fuel pipes are constructed of steel.

Nylon Fuel Pipes

CAUTIONIn order to reduce the risk of fire and personal injury observe the following items: Replace all nylon fuel pipes that are nicked, scratched or damaged during installation, do not attempt to repair the sections of the nylon fuel pipes Do not hammer directly on the fuel harness body clips when installing new fuel pipes. Damage to the nylon pipes may result in a fuel leak. Always cover nylon vapor pipes with a wet towel before using a torch near them. Also, never expose the vehicle to temperatures higher than 115°C (239°F) for more than one hour, or more than 90°C (194°F) for any extended period. Apply a few drops of clean engine oil to the male pipe ends before connecting fuel pipe fittings. This will ensure proper reconnection and prevent a possible fuel leak. (During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.)

Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There are 3 sizes of nylon pipes used

  1. 9.53 mm (3/8 in) ID for the fuel feed
  2. 7.94 mm (5/16 in) ID for the fuel return
  3. 12.7 mm (1/2 in) ID for the vent

Heat resistant rubber hose or corrugated plastic conduit protect the sections of the pipes that are exposed to chafing, high temperature, or vibration.

Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if nylon fuel pipes are forced into sharp bends, the pipes kink and restrict the fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Take special care when working on a vehicle with nylon fuel pipes.

Quick-Connect Fittings

Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the fittings together.

Fuel Pipe O-Rings

O-rings seal the threaded connections in the fuel system. The fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.

Scheme 120

Scheme 120: Fuel Meter Body Assembly
Scheme 120: Fuel Meter Body Assembly

The fuel meter body assembly (1) attaches to the lower intake manifold. The fuel meter body assembly performs the following functions

  1. Distributes fuel evenly to the injectors (3)
  2. Integrates the fuel pressure regulator (6) into the fuel metering system

Fuel Injectors

The Multec 2 fuel injector assembly is a solenoid device controlled by the control module that meters pressurized fuel to a single engine cylinder. The control module energizes the high-impedance, 12 ohms, injector solenoid to open a normally closed ball valve. This allows fuel to flow into the top of the injector, past the ball valve, and through a director plate at the injector outlet. The director plate has four machined holes that control the fuel flow, generating a spray of finely atomized fuel at the injector tip. Fuel from the injector tip is directed at the intake valve, causing the fuel to become further atomized and vaporized before entering the combustion chamber. This fine atomization improves fuel economy and emissions.

Scheme 121

Scheme 121: Fuel Pressure Regulator Assembly
Scheme 121: Fuel Pressure Regulator Assembly

The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure and intake manifold vacuum on the other side. The fuel pressure regulator maintains a constant pressure differential across the fuel injectors under all operating conditions. The fuel pressure regulator compensates for engine load by increasing fuel pressure as the engine vacuum drops.

Fuel Metering Modes of Operation

The control module monitors voltages from several sensors in order to determine how much fuel to give the engine. The control module controls the amount of fuel delivered to the engine by changing the fuel injector pulse width. The fuel is delivered under one of several modes.

Starting Mode

When the ignition is first turned ON, the control module energizes the fuel pump relay for 2 seconds. This allows the fuel pump to build pressure in the fuel system. The control module calculates the air/fuel ratio based on inputs from the engine coolant temperature (ECT), mass air flow (MAF), manifold absolute pressure (MAP), and throttle position (TP) sensors. The system stays in starting mode until the engine speed reaches a predetermined RPM.

Clear Flood Mode

If the engine floods, clear the engine by pressing the accelerator pedal down to the floor and then crank the engine. When the TP sensor is at wide open throttle (WOT), the control module reduces the fuel injector pulse width in order to increase the air to fuel ratio. The control module holds this injector rate as long as the throttle stays wide open and the engine speed is below a predetermined RPM. If the throttle is not held wide open, the control module returns to the starting mode.

Run Mode

The run mode has 2 conditions called Open Loop and Closed Loop. When the engine is first started and the engine speed is above a predetermined RPM, the system begins Open Loop operation. The control module ignores the signal from the heated oxygen sensor (HO2S). The control module calculates the air/fuel ratio based on inputs from the ECT, MAF, MAP, and TP sensors. The system stays in Open Loop until meeting the following conditions

  1. The HO2S has varying voltage output, showing that the HO2S is hot enough to operate properly.
  2. The ECT sensor is above a specified temperature.
  3. A specific amount of time has elapsed after starting the engine.

Specific values for the above conditions exist for each different engine, and are stored in the electrically erasable programmable read-only memory (EEPROM). The system begins Closed Loop operation after reaching these values. In Closed Loop, the control module calculates the air/fuel ratio, injector ON time, based upon the signal from various sensors, but mainly from the HO2S. This allows the air/fuel ratio to stay very close to 14.7:1.

Acceleration Mode

When the driver pushes on the accelerator pedal, air flow into the cylinders increases rapidly. To prevent possible hesitation, the control module increases the pulse width to the injectors to provide extra fuel during acceleration. This is also known as power enrichment. The control module determines the amount of fuel required based upon the TP, the ECT, the MAP, the MAF, and the engine speed.

Deceleration Mode

When the driver releases the accelerator pedal, air flow into the engine is reduced. The control module monitors the corresponding changes in the TP, the MAP, and the MAF. The control module shuts OFF fuel completely if the deceleration is very rapid, or for long periods, such as long, closed-throttle coast-down. The fuel shuts OFF in order to prevent damage to the catalytic converters.

Battery Voltage Correction Mode

When the battery voltage is low, the control module compensates for the weak spark delivered by the ignition system in the following ways

  1. Increasing the amount of fuel delivered
  2. Increasing the idle RPM
  3. Increasing the ignition dwell time

Fuel Cutoff Mode

The control module cuts OFF fuel from the fuel injectors when the following conditions are met in order to protect the powertrain from damage and improve driveability

  1. The ignition is OFF. This prevents engine run-on.
  2. The ignition is ON but there is no ignition reference signal. This prevents flooding or backfiring.
  3. The engine speed is too high, above red line.
  4. The vehicle speed is too high, above rated tire speed.
  5. During an extended, high speed, closed throttle coast down-This reduces emissions and increases engine braking.
  6. During extended deceleration, in order to prevent damage to the catalytic converters

Fuel Trim

The control module controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The control module monitors the HO2S signal voltage while in Closed Loop and regulates the fuel delivery by adjusting the pulse width of the injectors based on this signal. The ideal fuel trim values are around 0 percent for both short and long term fuel trim. A positive fuel trim value indicates the control module is adding fuel in order to compensate for a lean condition by increasing the pulse width. A negative fuel trim value indicates that the control module is reducing the amount of fuel in order to compensate for a rich condition by decreasing the pulse width. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltage. These changes fine tune the engine fueling. The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. A scan tool can be used to monitor the short and long term fuel trim values. The long term fuel trim diagnostic is based on an average of several of the long term speed load learn cells. The control module selects the cells based on the engine speed and engine load. If the control module detects an excessively lean or rich condition, the control module will set a fuel trim diagnostic trouble code (DTC).

EVAP System Operation

The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.

Large Leak Test

This tests for large leaks and blockages in the evaporative emission (EVAP) system. The control module commands the EVAP vent solenoid valve ON and commands the EVAP purge solenoid valve ON, with the engine running, allowing engine vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. The control module then commands the EVAP purge solenoid valve OFF, sealing the system, and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved, or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 will set.

Small Leak Test

The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.

The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.

The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.

Canister Vent Restriction Test

If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.

Purge Solenoid Valve Leak Test

If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.

Check Gas Cap Message

The powertrain control module (PCM) sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when any of the following occur

  1. A malfunction in the evaporative emission (EVAP) system and a large leak test fails
  2. A malfunction in the EVAP system and a small leak test fails

EVAP System Components

The evaporative emission (EVAP) system consists of the following components

EVAP Canister

The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.

EVAP Purge Solenoid Valve

The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.

EVAP Vent Solenoid Valve

The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.

Fuel Tank Pressure Sensor

The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.

EVAP Service Port

The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid valve and the EVAP canister. The service port is identified by a green colored cap.

Distributor Ignition (DI) System Description

The distributor ignition (DI) system is responsible for producing and controlling a high energy secondary spark. This spark is used to ignite the compressed air/fuel mixture at precisely the correct time. This provides optimal performance, fuel economy, and control of exhaust emissions. This ignition system consists of a single ignition coil and ignition control module (ICM). Spark energy is delivered via a distributor cap, rotor, and secondary spark plug wires. The driver module within the ICM is commanded to operate the coil by the powertrain control module (PCM), that has complete control over spark timing. The DI system consists of the following components

Crankshaft Position (CKP) Sensor

The CKP sensor is a three wire sensor based on the magneto resistive principle. A magneto resistive sensor uses two magnetic pickups between a permanent magnet. As an element such as a reluctor wheel passes the magnets the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The PCM supplies a 12-volt, low reference, and signal circuit to the CKP sensor. The sensor returns a digital ON/OFF pulse 3 times per crankshaft revolution for the V6 engine, 4 times for the V8 engine. The CKP sensor reads the crankshaft mounted reluctor wheel to identify pairs of cylinders at top dead center (TDC).

Camshaft Position (CMP) Sensor

The CMP sensor is a hall-effect sensor located in the ignition distributor base, and uses the same type of circuits as the CKP sensor. The CMP sensor signal is a digital ON/OFF pulse, output once per revolution of the camshaft. The CMP sensor information is used by the PCM to determine the position of the valve train relative to the CKP.

Ignition Coil & ICM

The ICM is connected to the PCM by an ignition control (IC) circuit. The ICM also has a ground circuit and shares an ignition 1 voltage supply with the ignition coil. The coil driver in the ICM controls current through the ignition coil based on signal pulses from the PCM. There is no back-up or by-pass function in the ICM.

Secondary Ignition Components

The distributor is only used as a means to operate the CMP sensor and to distribute spark in the correct sequence. Since the distributor has no influence on base timing the distributor is not adjustable on V6 engines. The distributor position can be adjusted on V8 engines because the chance of crossfire between terminals is greater due to the proximity of the terminals. The spark is distributed through conventional carbon core wires to the spark plugs. The plugs are tipped with platinum for long wear and higher efficiency.

Powertrain Control Module (PCM)

The PCM controls all ignition system functions, and constantly corrects the basic spark timing. The PCM monitors information from various sensor inputs that include the following

  1. The throttle position (TP) sensor
  2. The engine coolant temperature (ECT) sensor
  3. The mass airflow (MAF) sensor
  4. The intake air temperature (IAT) sensor
  5. The vehicle speed sensor (VSS)
  6. The transmission gear position or range information sensors
  7. The engine knock sensors (KS)

Modes of Operation

There is one normal mode of operation, with the spark under PCM control. If the CKP pulses are lost the engine will not run. The loss of a CMP signal may result in a longer crank time since the PCM cannot determine which stroke the pistons are on. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.

Purpose

The knock sensor (KS) system enables the control module to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The control module uses the KS system to test for abnormal engine noise that may indicate detonation, also known as spark knock.

Sensor Description

This KS system uses one or two flat response two-wire sensors. The sensor uses piezo-electric crystal technology that produces an AC voltage signal of varying amplitude and frequency based on the engine vibration or noise level. The amplitude and frequency are dependent upon the level of knock that the KS detects. The control module receives the KS signal through a signal circuit. The KS ground is supplied by the control module through a low reference circuit.

The control module learns a minimum noise level, or background noise, at idle from the KS and uses calibrated values for the rest of the RPM range. The control module uses the minimum noise level to calculate a noise channel. A normal KS signal will ride within the noise channel. As engine speed and load change, the noise channel upper and lower parameters will change to accommodate the normal KS signal, keeping the signal within the channel. In order to determine which cylinders are knocking, the control module only uses KS signal information when each cylinder is near top dead center (TDC) of the firing stroke. If knock is present, the signal will range outside of the noise channel.

If the control module has determined that knock is present, it will retard the ignition timing to attempt to eliminate the knock. The control module will always try to work back to a zero compensation level, or no spark retard. An abnormal KS signal will stay outside of the noise channel or will not be present. KS diagnostics are calibrated to detect faults with the KS circuitry inside the control module, the KS wiring, or the KS voltage output. Some diagnostics are also calibrated to detect constant noise from an outside influence such as a loose/damaged component or excessive engine mechanical noise.

Air Intake System Description

The primary function of the air intake system is to provide filtered air to the engine. The system uses a cleaner element mounted in a housing. The cleaner housing is remotely mounted and uses intake ducts to route the incoming air into the throttle body. The secondary function of the air intake system is to muffle air induction noise. This is achieved through the use of resonators attached to the air intake ducts. the resonators are tuned to the specific powertrain. The mass air flow (MAF) sensor is attached to the outlet of the air cleaner housing. The air cleaner life indicator is located on an intake duct between the air cleaner housing and the throttle plate.

Special Tools

Special Tools & Equipment Illustration Tool Number/Description GE 41415-50 Fuel Tank Cap Adapter J 26792 Spark Plug Tester J 34730-1A Fuel Pressure Gage J 34730-375 Harness Test Lamp J 35616-A Connector Test Adapter Kit J 37027-1A IAC Motor Driver You may also use an IAC Motor Driver from one of the approved manufacturers listed below: OTC Thexton CTI Snap On MAC Tools NAPA/Balkamp J 37088-A Fuel Line Disconnect Tool Set J 37287 Fuel Line Shut-off Adapters J 38522 Variable Signal Generator J 39021 Fuel Injector Coil and Balance Tester J 39021-210 Injector Tester Adapter Box J 39021-301 Injector Harness Connector J 39194 Oxygen Sensor Wrench J 39765 Fuel Sender Locknut Wrench J 41413-200 Evaporative Emissions System Tester (EEST) J 41413-SPT High Intensity White Light J 41413-VLV EVAP Service Port Vent Fitting J 41415-40 Fuel Tank Cap Adapter J 41416 Ultrasonic Leak Detector J 44175 Fuel Composition Tester

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